Hundreds of migrants huddled in the cold around campfires on Tuesday near the Belarus-Poland border, where razor wire fences and Polish border guards .
The EU vowed more sanctions on Belarus, accusing President Alexander Lukashenko of using "gangster-style" tactics in the months-long border standoff in which at least seven migrants have died.
Poland and other EU member states accuse Belarus of encouraging the migrants - from the Middle East, Afghanistan and Africa - to illegally cross the border into the EU in revenge for sanctions slapped on Minsk over human rights abuses.
"The Belarusian regime is attacking the Polish border, the EU, in an unparalleled manner," Polish President Andrzej Duda told a news conference in Warsaw.
"We currently have a camp of migrants who are blocked from the Belarusian side. There are about 1,000 people there, mostly young men. These are aggressive actions that we must repel, fulfilling our obligations as a member of the European Union."
Reuters reporters saw Polish border guards detain a group of migrants in a forest on the Polish side of the border on Tuesday afternoon. Medics were seen putting blankets around some of the migrants. One woman was unable to walk.
A handout picture shows Polish servicemen reinforcing the border line with barbed wire Source: BELTA
Prime Minister Mateusz Morawiekci, who earlier visited Polish troops stationed at the border, said the migrants were being used by Belarus as part of "a new type of war in which people are used as human shields".
He also accused Russian leader Vladimir Putin of orchestrating the crisis and threatening to destabilise the European Union.
"This attack which Lukashenko is conducting has its mastermind in Moscow, the mastermind is President Putin," Mr Morawiecki told an emergency session of the Polish parliament.
Mr Lukashenko's government, which is backed by Russia, denies engineering the migrant crisis and blames Europe and the United States for the plight of the people stranded at the border.
It summoned Poland's defence attache on Tuesday to protest what it said were unfounded allegations about the involvement of Belarusian military personnel in the crisis.
'Blackmail'
Mr Lukashenko and Mr Putin discussed the situation by phone and expressed concern over the build-up of Polish troops at the border, the Belarusian state news agency Belta reported on Tuesday.
"To conduct a war with these unfortunate people on the border of Poland with Belarus and move forward columns of tanks - it's clear this is either a training exercise or it's blackmail," Mr Lukashenko said in televised comments.
"We will calmly stand up to this," he added.
Russia's Foreign Minister Sergei Lavrov suggested the EU provide Belarus with financial assistance to stop the migrant flows, referencing an earlier deal with Turkey.
The European Commission said around 2,000 migrants were now gathered at the border.
"This is part of the inhuman and really gangster-style approach of the Lukashenko regime that he is lying to people, he is misusing people... and bringing them to Belarus under the false promise of having easy entry into the EU," a Commission spokesperson said.
EU governments partially suspended a visa facilitation deal for Belarusian officials.
The UN refugee agency, UNHCR, called for an end to the use of vulnerable people as political pawns.
'Dangerous events'
A spokesman for Poland's special services, Stanislaw Zaryn, said Belarusian security personnel were "firing empty shots into the air, simulating dangerous events", while also providing tools to the migrants to help them destroy the border fence.
On Monday some migrants used spades and other implements to try to break down the border fence.
Poland's Border Guard registered 309 illegal attempts to breach the frontier on Monday and detained 17 people, mainly Iraqis.
Lithuania also reported a surge in attempted migrant crossings and followed in Poland's footsteps by declaring a state of emergency on its border on Tuesday.
The move allows border guards to use "mental coercion" and "proportional physical violence" to stop the migrants.
The crisis erupted after Western powers slapped sanctions on Belarus over its violent crackdown on mass street protests that were sparked by Mr Lukashenko's claim of victory in a presidential election in 2020.
His opponents say the vote was rigged, which he denies.
Humanitarian groups accuse Poland 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.
A poll by IBRiS for Polish daily Rzeczpospolita this week showed 55 per cent of Poles believe migrants who have illegally crossed the border should be pushed back.
