Six masked protesters have surrendered in Hong Kong, bringing to about 30 the number that have come out in the past day from a university campus surrounded by police.

The group held hands as they walked toward a checkpoint before dawn Friday. Police are arresting all the adults. Those under 18 can go home but may face charges later.

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Protesters surrender themselves to police outside the Hong Kong Polytechnic University campus in Hong Kong, Friday, Nov. 22, 2019. More than 20 protesters inside a Hong Kong university campus surrendered to police on Thursday as the city's largest pro-Beijing political party urged voters to "kick out the black force" in upcoming elections seen as a key gauge of public support for anti-government demonstrations. (AP PhotoKin Cheung)

Six masked protesters have surrendered in Hong Kong, bringing to about 30 the number that have come out in the past day from a university campus surrounded by police.

Protesters surrender themselves to police outside the Hong Kong Polytechnic University campus in Hong Kong, Friday, Nov. 22, 2019. More than 20 protesters inside a Hong Kong university campus surrendered to police on Thursday as the city's largest pro-Beijing political party urged voters to "kick out the black force" in upcoming elections seen as a key gauge of public support for anti-government demonstrations. (AP PhotoKin Cheung)

The anti-government protesters battled with police and blocked the nearby approach to a major road tunnel, which remains closed.

A resident reacts after finding his route home blocked by riot police in the Yuen Long area in Hong Kong, Thursday, Nov. 21, 2019. More than 20 protesters inside a Hong Kong university campus surrendered to police on Thursday as the city's largest pro-Beijing political party urged voters to "kick out the black force" in upcoming elections seen as a key gauge of public support for anti-government demonstrations. (AP PhotoNg Han Guan)

A resident reacts after finding his route home blocked by riot police in the Yuen Long area in Hong Kong, Thursday, Nov. 21, 2019. More than 20 protesters inside a Hong Kong university campus surrendered to police on Thursday as the city's largest pro-Beijing political party urged voters to "kick out the black force" in upcoming elections seen as a key gauge of public support for anti-government demonstrations. (AP PhotoNg Han Guan)

People react as riot police shine a spotlight on them in the Yuen Long area in Hong Kong, Thursday, Nov. 21, 2019. More than 20 protesters inside a Hong Kong university campus surrendered to police on Thursday as the city's largest pro-Beijing political party urged voters to "kick out the black force" in upcoming elections seen as a key gauge of public support for anti-government demonstrations. (AP PhotoNg Han Guan)

People react as riot police shine a spotlight on them in the Yuen Long area in Hong Kong, Thursday, Nov. 21, 2019. More than 20 protesters inside a Hong Kong university campus surrendered to police on Thursday as the city's largest pro-Beijing political party urged voters to "kick out the black force" in upcoming elections seen as a key gauge of public support for anti-government demonstrations. (AP PhotoNg Han Guan)

A protester wears a Guy Fawkes mask during a sit-in at a shopping mall to commemorate the four-month anniversary of an assault on commuters and protesters by armed men at a nearby train station in Hong Kong, Thursday, Nov. 21, 2019.More than 20 protesters inside a Hong Kong university campus surrendered to police on Thursday as the city's largest pro-Beijing political party urged voters to "kick out the black force" in upcoming elections seen as a key gauge of public support for anti-government demonstrations. (AP PhotoNg Han Guan)

A protester wears a Guy Fawkes mask during a sit-in at a shopping mall to commemorate the four-month anniversary of an assault on commuters and protesters by armed men at a nearby train station in Hong Kong, Thursday, Nov. 21, 2019.More than 20 protesters inside a Hong Kong university campus surrendered to police on Thursday as the city's largest pro-Beijing political party urged voters to "kick out the black force" in upcoming elections seen as a key gauge of public support for anti-government demonstrations. (AP PhotoNg Han Guan)

Protesters gather during a rally in Sun Yat Sen Memorial Park in Hong Kong, Thursday, Nov. 21, 2019. More than 20 protesters inside a Hong Kong university campus surrendered to police on Thursday as the city's largest pro-Beijing political party urged voters to "kick out the black force" in upcoming elections seen as a key gauge of public support for anti-government demonstrations. (AP PhotoAchmad Ibrahim)

Protesters gather during a rally in Sun Yat Sen Memorial Park in Hong Kong, Thursday, Nov. 21, 2019. More than 20 protesters inside a Hong Kong university campus surrendered to police on Thursday as the city's largest pro-Beijing political party urged voters to "kick out the black force" in upcoming elections seen as a key gauge of public support for anti-government demonstrations. (AP PhotoAchmad Ibrahim)

Protesters gather during a rally in Sun Yat Sen Memorial Park in Hong Kong, Thursday, Nov. 21, 2019. More than 20 protesters inside a Hong Kong university campus surrendered to police on Thursday as the city's largest pro-Beijing political party urged voters to "kick out the black force" in upcoming elections seen as a key gauge of public support for anti-government demonstrations. (AP PhotoAchmad Ibrahim)

Protesters gather during a rally in Sun Yat Sen Memorial Park in Hong Kong, Thursday, Nov. 21, 2019. More than 20 protesters inside a Hong Kong university campus surrendered to police on Thursday as the city's largest pro-Beijing political party urged voters to "kick out the black force" in upcoming elections seen as a key gauge of public support for anti-government demonstrations. (AP PhotoAchmad Ibrahim)

Protesters gather during a rally in Sun Yat Sen Memorial Park in Hong Kong, Thursday, Nov. 21, 2019. More than 20 protesters inside a Hong Kong university campus surrendered to police on Thursday as the city's largest pro-Beijing political party urged voters to "kick out the black force" in upcoming elections seen as a key gauge of public support for anti-government demonstrations. (AP PhotoAchmad Ibrahim)

Protesters gather during a rally in Sun Yat Sen Memorial Park in Hong Kong, Thursday, Nov. 21, 2019. More than 20 protesters inside a Hong Kong university campus surrendered to police on Thursday as the city's largest pro-Beijing political party urged voters to "kick out the black force" in upcoming elections seen as a key gauge of public support for anti-government demonstrations. (AP PhotoAchmad Ibrahim)

Most of the protesters who took over Hong Kong Polytechnic University last week have left, but an unknown number remain inside.

Protesters surrender themselves to police outside the Hong Kong Polytechnic University campus in Hong Kong, Friday, Nov. 22, 2019. More than 20 protesters inside a Hong Kong university campus surrendered to police on Thursday as the city's largest pro-Beijing political party urged voters to "kick out the black force" in upcoming elections seen as a key gauge of public support for anti-government demonstrations. (AP PhotoKin Cheung)

Protesters surrender themselves to police outside the Hong Kong Polytechnic University campus in Hong Kong, Friday, Nov. 22, 2019. More than 20 protesters inside a Hong Kong university campus surrendered to police on Thursday as the city's largest pro-Beijing political party urged voters to "kick out the black force" in upcoming elections seen as a key gauge of public support for anti-government demonstrations. (AP PhotoKin Cheung)

The anti-government protesters battled with police and blocked the nearby approach to a major road tunnel, which remains closed.

It was the latest bout in more than five months of unrest. Protesters are demanding fully democratic elections and an investigation into alleged police brutality in suppressing the demonstrations.

Protesters surrender themselves to police outside the Hong Kong Polytechnic University campus in Hong Kong, Friday, Nov. 22, 2019. More than 20 protesters inside a Hong Kong university campus surrendered to police on Thursday as the city's largest pro-Beijing political party urged voters to "kick out the black force" in upcoming elections seen as a key gauge of public support for anti-government demonstrations. (AP PhotoKin Cheung)

Protesters surrender themselves to police outside the Hong Kong Polytechnic University campus in Hong Kong, Friday, Nov. 22, 2019. More than 20 protesters inside a Hong Kong university campus surrendered to police on Thursday as the city's largest pro-Beijing political party urged voters to "kick out the black force" in upcoming elections seen as a key gauge of public support for anti-government demonstrations. (AP PhotoKin Cheung)

A resident reacts after finding his route home blocked by riot police in the Yuen Long area in Hong Kong, Thursday, Nov. 21, 2019. More than 20 protesters inside a Hong Kong university campus surrendered to police on Thursday as the city's largest pro-Beijing political party urged voters to "kick out the black force" in upcoming elections seen as a key gauge of public support for anti-government demonstrations. (AP PhotoNg Han Guan)

A resident reacts after finding his route home blocked by riot police in the Yuen Long area in Hong Kong, Thursday, Nov. 21, 2019. More than 20 protesters inside a Hong Kong university campus surrendered to police on Thursday as the city's largest pro-Beijing political party urged voters to "kick out the black force" in upcoming elections seen as a key gauge of public support for anti-government demonstrations. (AP PhotoNg Han Guan)

People react as riot police shine a spotlight on them in the Yuen Long area in Hong Kong, Thursday, Nov. 21, 2019. More than 20 protesters inside a Hong Kong university campus surrendered to police on Thursday as the city's largest pro-Beijing political party urged voters to "kick out the black force" in upcoming elections seen as a key gauge of public support for anti-government demonstrations. (AP PhotoNg Han Guan)

People react as riot police shine a spotlight on them in the Yuen Long area in Hong Kong, Thursday, Nov. 21, 2019. More than 20 protesters inside a Hong Kong university campus surrendered to police on Thursday as the city's largest pro-Beijing political party urged voters to "kick out the black force" in upcoming elections seen as a key gauge of public support for anti-government demonstrations. (AP PhotoNg Han Guan)

A protester wears a Guy Fawkes mask during a sit-in at a shopping mall to commemorate the four-month anniversary of an assault on commuters and protesters by armed men at a nearby train station in Hong Kong, Thursday, Nov. 21, 2019.More than 20 protesters inside a Hong Kong university campus surrendered to police on Thursday as the city's largest pro-Beijing political party urged voters to "kick out the black force" in upcoming elections seen as a key gauge of public support for anti-government demonstrations. (AP PhotoNg Han Guan)

A protester wears a Guy Fawkes mask during a sit-in at a shopping mall to commemorate the four-month anniversary of an assault on commuters and protesters by armed men at a nearby train station in Hong Kong, Thursday, Nov. 21, 2019.More than 20 protesters inside a Hong Kong university campus surrendered to police on Thursday as the city's largest pro-Beijing political party urged voters to "kick out the black force" in upcoming elections seen as a key gauge of public support for anti-government demonstrations. (AP PhotoNg Han Guan)

Protesters gather during a rally in Sun Yat Sen Memorial Park in Hong Kong, Thursday, Nov. 21, 2019. More than 20 protesters inside a Hong Kong university campus surrendered to police on Thursday as the city's largest pro-Beijing political party urged voters to "kick out the black force" in upcoming elections seen as a key gauge of public support for anti-government demonstrations. (AP PhotoAchmad Ibrahim)

Protesters gather during a rally in Sun Yat Sen Memorial Park in Hong Kong, Thursday, Nov. 21, 2019. More than 20 protesters inside a Hong Kong university campus surrendered to police on Thursday as the city's largest pro-Beijing political party urged voters to "kick out the black force" in upcoming elections seen as a key gauge of public support for anti-government demonstrations. (AP PhotoAchmad Ibrahim)

Protesters gather during a rally in Sun Yat Sen Memorial Park in Hong Kong, Thursday, Nov. 21, 2019. More than 20 protesters inside a Hong Kong university campus surrendered to police on Thursday as the city's largest pro-Beijing political party urged voters to "kick out the black force" in upcoming elections seen as a key gauge of public support for anti-government demonstrations. (AP PhotoAchmad Ibrahim)

Protesters gather during a rally in Sun Yat Sen Memorial Park in Hong Kong, Thursday, Nov. 21, 2019. More than 20 protesters inside a Hong Kong university campus surrendered to police on Thursday as the city's largest pro-Beijing political party urged voters to "kick out the black force" in upcoming elections seen as a key gauge of public support for anti-government demonstrations. (AP PhotoAchmad Ibrahim)

Protesters gather during a rally in Sun Yat Sen Memorial Park in Hong Kong, Thursday, Nov. 21, 2019. More than 20 protesters inside a Hong Kong university campus surrendered to police on Thursday as the city's largest pro-Beijing political party urged voters to "kick out the black force" in upcoming elections seen as a key gauge of public support for anti-government demonstrations. (AP PhotoAchmad Ibrahim)

Protesters gather during a rally in Sun Yat Sen Memorial Park in Hong Kong, Thursday, Nov. 21, 2019. More than 20 protesters inside a Hong Kong university campus surrendered to police on Thursday as the city's largest pro-Beijing political party urged voters to "kick out the black force" in upcoming elections seen as a key gauge of public support for anti-government demonstrations. (AP PhotoAchmad Ibrahim)