British and European Union negotiators plan to work through the weekend to see if they can agree a Brexit deal in time for next week's summit of EU leaders.

The EU's chief negotiator, Michel Barnier, approved an intensification of the discussions after British Prime Minister Boris Johnson and his Irish counterpart, Leo Varadkar, said they could see a "pathway" forward following talks on Thursday.

European Council President Donald Tusk said Friday he could see the talks in Brussels going through the weekend, ahead of the EU summit, which starts Thursday.

Two anti-Brexit people hold EU, Ireland and Union Flags stand outside the European Commission in Brussels, Friday, Oct. 11, 2019. EU negotiator Michel Barnier says that he had a "constructive meeting" with British Brexit envoy Stephen Barclay and underscored the cautious optimism since Thursday's meeting between British Prime Minister Boris Johnson and his Irish counterpart Leo Varadkar. (AP PhotoFrancisco Seco)

Two anti-Brexit people hold EU, Ireland and Union Flags stand outside the European Commission in Brussels, Friday, Oct. 11, 2019. EU negotiator Michel Barnier says that he had a "constructive meeting" with British Brexit envoy Stephen Barclay and underscored the cautious optimism since Thursday's meeting between British Prime Minister Boris Johnson and his Irish counterpart Leo Varadkar. (AP PhotoFrancisco Seco)

The main stumbling block remains the border between Northern Ireland and Ireland, the United Kingdom's only land border with the EU. It has dominated talks ever since U.K. voters chose in 2016 to leave the EU.

Follow AP's full coverage of Brexit and British politics at https://www.apnews.com/Brexit

Two anti Brexit people hold EU, Ireland and Union Flags as they wait for the departure of UK Brexit secretary Stephen Barclay during his meeting with European Union chief Brexit negotiator Michel Barnier at the European Commission headquarters in Brussels, Friday, Oct. 11, 2019. The European Union said Friday that talks with the United Kingdom to find an amicable divorce with the United Kingdom are back on track, despite huge challenges and a tight end-of-month deadlime looming large. (AP PhotoFrancisco Seco)

Two anti Brexit people hold EU, Ireland and Union Flags as they wait for the departure of UK Brexit secretary Stephen Barclay during his meeting with European Union chief Brexit negotiator Michel Barnier at the European Commission headquarters in Brussels, Friday, Oct. 11, 2019. The European Union said Friday that talks with the United Kingdom to find an amicable divorce with the United Kingdom are back on track, despite huge challenges and a tight end-of-month deadlime looming large. (AP PhotoFrancisco Seco)