On Monday, Polish police accused Belarus of attempting to incite a huge clash after social media footage showed hundreds of refugees going towards the Polish border.

Migrants carrying rucksacks and dressed in cold apparel were spotted walking on the side of a motorway in one video uploaded by the Belarusian blogging service NEXTA.

In other footage, big groups of migrants sat beside the road, escorted by armed personnel clad in khaki.

“Belarus intends to produce a large incident, preferably with bullets fired and casualties: according to media sources, they are planning a major provocation near Kuznica Bialostocka, with an attempt at a mass border crossing,” Deputy Foreign Minister Piotr Wawrzyk told Polish public radio.

Maciej Wasik, deputy interior minister, stated that “Polish authorities are prepared for any scenario.”

The European Union has accused Belarus of pushing thousands of migrants from the Middle East and Africa to enter EU nations via Belarus as a sort of hybrid warfare in retaliation for Western sanctions imposed on Minsk for human rights violations.

Belarusian President Alexander Lukashenko’s government has repeatedly denied manufacturing a migrant crisis, blaming the West for the crossings and the treatment of migrants at the border.

The Belarusian state border committee issued a statement confirming that a large group of refugees was moving along the highway to the Polish border, and saying Warsaw was taking an “inhumane attitude”.

The EU, the United States and Britain imposed sanctions on Belarus after Lukashenko unleashed a violent crackdown on mass protests following a disputed election last year.

Charities say the migrants face grueling conditions while trying to cross the border from Belarus, enduring freezing weather and a lack of food, water and medical attention.

Polish authorities say at least seven dead migrants have been found on Poland’s side of the border, with unverified reports of more deaths in Belarus.

Humanitarian groups accuse Poland’s ruling nationalists of violating the international right to asylum by pushing migrants back into Belarus instead of accepting their applications for protection. Poland says its actions are legal.

Poland’s Prime Minister Mateusz Morawiecki said on Facebook that “the Polish border is not just a line on a map. The border is sacred – Polish blood has been spilled for it!”.