COPENHAGEN - A formal letter of disapproval from the European Commission, sent to six European Union (EU) member states contravening the open border policy of the Schengen Treaty, has been met with silence or intransigence from government officials.

All six EU states have 10 days to respond to the commission after receiving the letter on Feb 22. According to the EU laws, if the member states fail to undertake necessary measures, the commission could take legal actions against them.

The four-page document, sent to Germany, Denmark, Finland, Sweden, Belgium and Hungary, highlights the commission's concern that their unilateral border control measures to curb the spread of the pandemic risk "fragmentation and disruptions to free movement and to supply chains", according to Christian Wigand, a spokesperson for the commission.

The German federal government has declared the Czech Republic, Slovakia and large parts of Tyrol in Austria as so-called "areas of variant of concern" since mid-February. The aim of its border controls is to prevent the more contagious COVID-19 variants from spreading into the country.

Minister of State for Europe at the German Federal Foreign Office Michael Roth said that the German government's actions are "in keeping with Schengen", the rules of Europe's passport-free travel zone.

However, the border restrictions have caused a diplomatic rift with the Austrian government, which recently summoned the German ambassador in Vienna to justify the "unnecessary measures that do more harm than good".

In an interview with the German newspaper Munchner Merkur, Austria's Chancellor Sebastian Kurz repeated his plea against permanent lockdowns and for extensive testings and a Europe-wide vaccination certificate.

"I hope that Europe will soon bring about a uniform procedure at the borders," said the chancellor.

Hungary has had its borders closed to nearly all foreigners since last September, following a spike of cases after the summer.

In response to the EU's criticism, the Hungarian government said that at the current moment it was not proper to point fingers at one another.

Hungarian Prime Minister Viktor Orban said on Friday that the next coming days would decide how to alter the current rules. The further tightening of security at the borders is one concerned area.

"At the borders, tightening is definitely needed due to the strong outbreak of the epidemic," Orban said.

Denmark also reaffirmed its stance on border controls after receiving the commission's letter.

Danish Prime Minister Mette Frederiksen asserted that Denmark had no intention of relaxing border controls.

"My position on border control is the same as it has been throughout. There in an epidemic, we need border control," said Frederiksen.

The prime minister further explained that the rise of new variants is the reason why Denmark will continue to maintain its border restrictions.

Sweden has a stricter entry ban for foreign citizens traveling from Denmark, Norway and Britain.

Facing complaints from many commuters crossing the Nordic borders for work, Anna Hallberg, Swedish minister for foreign trade and Nordic affairs, said she believed that "Nordic crisis management has broken down" and that "border cooperation requires more dialogue."

"When the crisis came, we did not think of the Nordic countries, but we thought in terms of national crisis management. When the sun is shining, the cooperation works, but not when it is raining and stormy. We must learn from that," Hallberg said.

Government officials in Finland have also cited the pandemic and the country's failure to find alternatives for border restrictions as grounds for maintaining their border controls.

"We're not in any kind of normal and business-as-usual situation but in the middle of a global pandemic," said Finland's Minister for European Affairs Tytti Tuppurainen.

She underscored that Finland is a supporter for the internal market and free mobility within the Schengen area.

However, its response to the pandemic has been designed with an emphasis on the health of citizens, she said.

"We think it (the border control) is ... important because the goal is to prevent the virus from spreading and especially the entry of these variants to Finland," said Tuppurainen.