The European Union's Baltic member states warned on Thursday of a possible military escalation in the stand-off about migrants trying to reach the European Union from Belarus.

The defence ministers of the Baltic states warned that the migrant bottlenecks, which the EU says are being deliberately created by Minsk, threaten a vast section of the bloc's eastern flank - and could even spark a military conflict.

"Large groups of people are gathered and transported to the border area, where they are then forced to cross the border illegally. This increases the possibility of provocations and serious incidents which could also spill over into the military sphere," Kalle Laanet of Estonia, Artis Pabriks of Latvia and Arvydas Anusauskas of Lithuania wrote in a joint statement.

They condemned the "deliberate escalation of the Belarusian regime's ongoing hybrid attack."

While stressing their countries' bilateral support for Poland, the ministers also called on the EU "to increase its practical support to improve security at its external borders."

Many hundreds of migrants, including many children, are staying in the open in near-freezing temperatures along Belarus' western border with the EU. Some have tents, others have only the nearby woods for shelter.

Mostly from the Middle East, they are caught between the authoritarian regime of Belarusian leader Alexander Lukashenko, who is accused of helping them reach the border area, while Polish authorities are refusing to let them into EU territory.

Lukashenko - sometimes dubbed "Europe's last dictator" - has stood firm in the face of increasing pressure on his regime. On Thursday he threatened to cut energy supplies to Europe.

"We heat Europe and they threaten to shut the borders," he told a meeting of senior officials on Thursday. "So what if we shut off the gas?"

Only a small proportion of gas reaches Europe through pipelines that cross Belarusian territory. Most arrives through Ukraine and the Baltic Nord Stream 1 pipeline.

Poland, which has been bolstering its border security for weeks, asked for help in preventing any breaches by the migrants, who now number in the low thousands.

Polish authorities reported on Thursday that a large group of migrants had tried during the night to break through to Polish territory.

An EU Commission spokesperson confirmed on Thursday that experts from Europol's anti-people-smuggling centre would be "supporting Poland in overcoming the current situation at the border."

The fierce row between Minsk and Brussels goes back to disputed elections in Belarus in August 2020 and Lukashenko's violent crackdown on protesters; since then, the EU has refused to recognize him as the country's legitimate leader and imposed sanctions. More sanctions are expected to soon in the escalating stand-off.

The new EU sanctions instrument, which could be used against airlines or tour operators, is expected to be formally adopted as early as Monday at a meeting of EU foreign ministers, according to diplomats.

German Foreign Minister Heiko Maas accused Lukashenko of playing an unscrupulous game with human lives and repeated the threat of sanctions - targeting not only the Belarusian state, but also transit countries and airlines helping to relocate the migrants.

"No one should be allowed to participate in Lukashenko's inhumane activities with impunity," Maas told the German parliament on Thursday.

German Interior Minister Horst Seehofer meanwhile called for solidarity for Poland and to help the country secure its border with Belarus, in comments published Friday by Funke media group.

"Poland is performing an important service here for all of Europe," Seehofer said. "We must count on the whole democratic world to support our policy."

Many of the migrants wish to apply for asylum in Germany.

Acting German Chancellor Angela Merkel has reached out to Russia in recent days to help de-escalate the crisis.

She spoke with President Vladimir Putin on the telephone on the second day in a row on Thursday, according to separate statements issued by Merkel's spokesperson and the Kremlin.

The Russian side noted that it was important to solve the migration crisis on the basis of international humanitarian norms and said that Putin had reiterated his plea for the restoration of communication between the EU and Belarus.

On Wednesday, Merkel appealed to Russia to use its influence on Minsk to find a way to resolve the growing tensions in the region.

After a UN Security Council meeting in New York on Thursday, the US, Britain, Estonia, France, Ireland, Norway and Albania condemned the "orchestrated instrumentalization of human beings whose lives and wellbeing have been put in danger for political purposes by Belarus."

They said Lukashenko's actions had the "objective of destabilizing neighbouring countries and the European Union’s external border and diverting attention away from its own increasing human rights violations."

dpa