EU members Poland and Lithuania say they are stepping up security at their borders with Belarus as Warsaw said that thousands of migrants were massing near the Belarusian side of the border.
In recent months, thousands of migrants from the Middle East, South Asia, and Africa have attempted to illegally enter Poland and fellow EU members Latvia and Lithuania from Belarus.
The EU has accused Belarusian strongman Alyaksandr Lukashenka of flying in migrants and funneling them to the bloc's borders to retaliate against Brussels for sanctions imposed over a sweeping crackdown on the political opposition, civil society, and independent media since last year's disputed presidential election.
Polish government spokesman Piotr Muller told reporters on November 8 that there were currently around 3,000-4,000 migrants near the Belarusian border with Poland, and thousands more ready to follow them.
The Defense Ministry in Warsaw on November 8 distributed a video which it said showed a group of migrants near the Bruzhi-Kuznica border crossing.
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Hundreds Of Migrants Gather At Belarusian-Polish Border
"Belarus wants to cause a major incident, preferably with shots fired and casualties," Deputy Foreign Minister Piotr Wawrzyk told Polish public radio the same day.
In one video posted on social media, people carrying rucksacks and wearing winter clothing are seen walking on the side of a highway with a billboard written in Belarusian.
Another video showed a large group of men and women escorted by armed men in military uniform.
Polish Defense Minister Mariusz Blaszczak tweeted on November 8 that more than 12,000 soldiers have been deployed on the border, up from the 10,000 soldiers that were there recently.
A volunteer Territorial Defense force was put on alert, he added.
He said that his ministry, together with the Interior Ministry, which is responsible for police and border guards, was "prepared to defend the Polish border."
SEE ALSO: On Poland's Border With Belarus, A Syrian Refugee's Desperate Battle To Save His FamilyInterior Minister Mariusz Kaminski said the Polish authorities were "prepared for any scenario."
"Tough defense of the border is our priority. We increased the number of Border Guard officers, police officers and soldiers. We are waiting in full readiness,” he wrote on Twitter.
The Belarusian State Border Committee said that the "inhumane attitude of the Polish authorities made the refugees to go for this step of despair."
The deepening crisis prompted calls for the EU to take swift action against Belarus to protect the bloc's borders, following repeated warnings and protests from Brussels.
"I am calling on member states to finally approve the extended sanctions regime on the Belarusian authorities responsible for this hybrid attack," European Commission President Ursula von der Leyen said after speaking with the prime ministers of Poland, Lithuania, and Latvia.
"The EU will in particular explore how to sanction, including through blacklisting, third-country airlines that are active in human trafficking," she said.
Poland has already imposed a state of emergency at the border, put up razor wire, and increased the number of soldiers and guards to stem the flow of migrants crossing from Belarus. Lawmakers have also approved the building of a $407 million wall on its eastern border.
The interior minister of neighboring Lithuania said on November 8 that her country was also moving troops to its border with Belarus to prepare for a possible influx of migrants.
The cabinet in Vilnius will also discuss whether to declare a state of emergency in the area bordering Belarus, Agne Bilotaite told a news conference.
She did not say how many soldiers would be deployed and precisely where they would be moved.
A NATO official called Minsk's alleged use of migrants to put pressure on the EU "unacceptable," and said the alliance was worried about "escalation" on the border with Poland.
The alliance, of which Poland, Lithuania, and Latvia are member states, "stands ready to further assist our allies, and maintain safety and security in the region," the official told the AFP news agency.
Meanwhile, exiled Belarusian opposition leader Svyatlana Tsikhanouskaya urged a "strong response" from the European Union, and said the matter should be discussed at the United Nations Security Council.
"Belarus' regime escalates the border crisis -- migrants are pushed to EU border by armed men. The migrant smuggling, violence & ill-treatment must stop," she tweeted.