Denmark’s Transport Ministry announced Thursday that it has suspended all passenger flights from the United Arab Emirates for five days. 

The decision stems from suspicions that Covid-19 tests taken by passengers before leaving Dubai are not reliable, the ministry said in a statement.

Transport Minister Benny Engelbrecht said passengers coming from Dubai have been diagnosed with fast-spreading variants of COVID-19 and the country will investigate the accuracy of the results of tests carried out in the UAE.

Effective Jan. 9, anyone traveling to Denmark must show proof of a negative coronavirus test no older than 24 hours.

On Wednesday, the Danish government decided to extend a coronavirus lockdown by three weeks until Feb. 7 due to concerns over a new variant of the virus.