Denmark has temporarily suspended all flights from the United Arab Emirates for five days after suspicion arose that the coronavirus tests that can be obtained before leaving Dubai are not reliable, authorities announced Friday.

The development poses a direct challenge to the mass testing regime that had been the pillar of the UAE's coronavirus response and economic reopening.

Danish Transport Minister Benny Engelbrecht said the decision was made to allow the matter to be thoroughly investigated and ensure that the testing are being carried out properly

Tourists on a yacht as they pass a traditional dhow serving a dinner cruise, in Dubai, United Arab Emirates, Tuesday, Jan. 12, 2021. With peak tourism season in full swing, coronavirus infections are surging to unprecedented heights, with daily case counts nearly tripling in the past month, forcing Britain to slam shut its travel corridor with Dubai last week. But in the face of a growing economic crisis, the city won't lock down and can't afford to stand still. (AP PhotoKamran Jebreili)

Tourists on a yacht as they pass a traditional dhow serving a dinner cruise, in Dubai, United Arab Emirates, Tuesday, Jan. 12, 2021. With peak tourism season in full swing, coronavirus infections are surging to unprecedented heights, with daily case counts nearly tripling in the past month, forcing Britain to slam shut its travel corridor with Dubai last week. But in the face of a growing economic crisis, the city won't lock down and can't afford to stand still. (AP PhotoKamran Jebreili)

“We can’t ignore such a suspicion,” Engelbrecht said, adding that the ban entered into force on Thursday night.

Danish authorities faced a “concrete and serious citizen inquiry into" how the tests are carried out at Dubai entry and exit points, he said, and “therefore we need to be absolutely sure that there are no problems.”

Engelbrecht said at least “one citizen” brought the South African variant of the virus “back from Dubai." He did not identify further that person. Dubai has seen an increase in the number of South African residents as the country's economy deteriorated in recent years.

Tourists party on a yacht in Dubai, United Arab Emirates, Tuesday, Jan. 12, 2021. Since becoming one of the world's first destinations to open up for tourism, Dubai has promoted itself as the ideal pandemic vacation spot. With peak tourism season in full swing, coronavirus infections are surging to unprecedented heights, with daily case counts nearly tripling in the past month, but in the face of a growing economic crisis, the city won't lock down and can't afford to stand still. (AP PhotoKamran Jebreili)

Tourists party on a yacht in Dubai, United Arab Emirates, Tuesday, Jan. 12, 2021. Since becoming one of the world's first destinations to open up for tourism, Dubai has promoted itself as the ideal pandemic vacation spot. With peak tourism season in full swing, coronavirus infections are surging to unprecedented heights, with daily case counts nearly tripling in the past month, but in the face of a growing economic crisis, the city won't lock down and can't afford to stand still. (AP PhotoKamran Jebreili)

Danish tabloid Ekstra Bladet said Friday there has been a second report of allegedly sloppy virus testing in Dubai, and cited Engelbrecht as saying “the information seem precise and valid.”

Since Jan. 9, Denmark has required that all passengers arriving in the Scandinavian country have a negative coronavirus test or proof that they have recently had COVID-19, the illness caused by the virus, to limit the spread of the virus.

The UAE’s Foreign Ministry did not immediately respond to an Associated Press request for comment on the flight suspension and the suspicions surrounding the virus testing.

Tourists and residents enjoy the sunset at the Jumeirah Beach Residence, in Dubai, United Arab Emirates, Tuesday, Jan. 12, 2021. Coronavirus infections are surging to unprecedented heights in the United Arab Emirates. But Dubai, the glimmering city-state powered by legions of foreign laborers and travelers, is resisting a lockdown during its peak tourism season. (AP PhotoKamran Jebreili)

Tourists and residents enjoy the sunset at the Jumeirah Beach Residence, in Dubai, United Arab Emirates, Tuesday, Jan. 12, 2021. Coronavirus infections are surging to unprecedented heights in the United Arab Emirates. But Dubai, the glimmering city-state powered by legions of foreign laborers and travelers, is resisting a lockdown during its peak tourism season. (AP PhotoKamran Jebreili)

On Jan. 8, Denmark’s Foreign Ministry advised against all travel abroad, including business travel. On Tuesday, Danish Prime Minister Mette Frederiksen told local media that “there is a reason why we really ask everyone not to travel. It’s really important that everyone listens."

“There is a risk of bringing (virus) mutations to Denmark," she said. “It can undermine our epidemic control and thus infect others and what is worse.”

In recent days, several Danish celebrities, socialites and influencers — such as former boxer Mikkel Kessler, former football international Nicklas Bendtner and table tennis ace Michael Maze — have traveled to Dubai and posted photos of themselves on social media.

Lea Hvidt Kessler, the wife of the former super-middleweight world champion, wrote on Instagram that no one in their family that traveled to Dubai before Christmas was infected. According to media in Denmark, there are currently 85 Danish nationals there and about 800 permanent Danish residents in Dubai.

Tourists have flocked to Dubai in recent weeks despite the UAE's surging coronavirus case count, escaping lockdowns back home. The glimmering city-state, with an economy largely built on tourism, aviation and retail, has promoted itself as an ideal pandemic vacation spot. Aside from the ubiquitous masks and hand sanitizer dispensers, a sense of pre-pandemic normalcy prevails in the crowded bars, massive malls and luxury hotels.

Skyrocketing daily infections, which nearly tripled since November, for weeks did not dent the normalcy even as more contagious variants of the coronavirus raced around the globe. The United Kingdom, which like Denmark sent droves of reality TV and sports stars to Dubai, closed its travel corridor with the UAE earlier this month.

This week, however, the city has shown signs of strain. As the UAE shattered its coronavirus infection for the 11th consecutive day on Friday, with 3,552 new cases, Dubai announced an immediate halt to all "entertainment activities" on boats and floating restaurants — a popular pastime in the city. Tourists and celebrities often flaunt their vacations on social media, posting photos of raucous, Champagne-soaked yacht parties that have splashed across tabloids in recent weeks. A day earlier, Dubai suspended all live bands and performances at nightclubs and bars in the city after hospitals were forced to pause non-urgent surgeries to deal with an influx of new COVID-19 patients.

Since the start of the pandemic, the UAE has built its coronavirus response on an “early detection strategy," embarking on one of the world's best coronavirus testing regimes at a time when other countries were struggling to obtain and administer PCR tests. As of Friday, the country of roughly 9 million had conducted some 24.2 million coronavirus tests.

Dubai was one of the world's first destinations to open up to tourists, welcoming visitors from anywhere with only a coronavirus test. The country has used Chinese-made coronavirus test kits in its race to detect infections. The U.S. State Department previously raised concerns that Chinese testing material was not accurate, without providing evidence about the allegation.

Associated Press writer Isabel DeBre in Dubai, United Arab Emirates, contributed to this report.