European Commission President Ursula von der Leyen and U.S. President Joe Biden discussed potentially imposing sanctions against airlines that bring migrants into Belarus during their meeting Wednesday, the Associated Press reported.

Mass influxes of migrants have been gathering along Belarus' shared borders with European Union members Poland, Lithuania and Latvia, prompting allegations that Belarusian President Alexander Lukashenko is sending them in an attempt to destabilize the bloc.

Von der Leyen said that Belarus' alleged targeting of the EU with the migrants "is an attempt by an authoritarian regime to try to destabilize democratic neighbors. This will not succeed."

Some have accused Lukashenko of pushing migrants toward the EU as retaliation for sanctions it imposed on Belarus for its crackdown on internal opposition since the contentious 2020 election. Belarus has denied the allegations, but said that it would no longer make efforts to stem the migrant flow, the AP reported.

Still, more and more leaders have accused Belarus of leveraging suffering migrants as political retaliation against the EU. German Chancellor Angela Merkel said that she asked Russian President Vladimir Putin Wednesday to "exert his influence on President Lukashenko because people are being used here."

"They are victims of an inhuman policy, and something must be done against this," Merkel said while speaking in Meseberg, which is near Berlin.

For more reporting from the Associated Press, see below:

European Commission President Ursula von der Leyen and U.S. President Joe Biden discussed potential sanctions against airlines that bring migrants into Belarus during their meeting Wednesday. Von der Leyen speaks outside the White House on November 10 in Washington, D.C.Win McNamee/Getty Images

Polish authorities estimate that about 3,000-4,000 migrants have gathered along its border with Belarus, with hundreds concentrated in one makeshift camp not far from the Kuznica crossing. Warsaw has bolstered security at the frontier, where it has declared a state of emergency.

Polish authorities have tweeted video of migrants, some using shovels and wire cutters, trying to break through a fence on the border to enter Poland.

"From a distance, these events on the Polish-Belarusian border may look like a migration crisis, but this is not a migration crisis, it is a political crisis triggered with the special purpose of destabilizing the situation in the European Union," said Polish Prime Minister Mateusz Morawiecki.

Steffen Seibert, a spokesman for Merkel, said in Berlin that Minsk is engaged in "state-run smuggling and trafficking...happening 100 percent at the expense of the people who are lured into the country with false promises."

Poland said Russia bears some responsibility for the crisis, given its staunch backing of Lukashenko. Germany's interior minister, Horst Seehofer, also accused Lukashenko of "using people's fates—with the support of Russian President Vladimir Putin—to destabilize the West."

Latvian Prime Minister Krisjanis Karins added that "it is what I would call a state-sponsored human trafficking, which is affecting directly my country, Lithuania and Poland."

The Kremlin's account of the call with Merkel said Putin proposed a discussion between "representatives of EU member states and Minsk." It also said Putin and Merkel "agreed to continue the conversation."

Kremlin spokesman Dmitry Peskov rejected suggestions by Morawiecki that Moscow has any responsibility in the crisis, calling them "absolutely irresponsible and unacceptable." Foreign Minister Sergey Lavrov also has suggested the EU give Belarus financial aid to stop the migrant flow.

U.S. Secretary of State Antony Blinken, who met in Washington with Ukrainian Foreign Minister Dmytro Kuleba, said "the idea that Belarus would weaponize migration is profoundly objectionable."

"We will continue to pressure Lukashenko and the regime, and we will not lessen our calls for accountability," he added. Kuleba said Belarus "is a potential front line that should not be underestimated."

European Council President Charles Michel met in Warsaw with Morawiecki in a gesture of solidarity, saying: "We are facing a hybrid, brutal, violent and unworthy attack, and we can only reply to this with firmness and unity, in accordance with our core values."

Michel also said the EU is discussing the possibility of funding "physical infrastructure" on its external borders. The EU's executive commission has long held that walls and barriers are not effective and has refused to fund them with money from the bloc. It would only pay for security cameras and surveillance equipment, not walls, fences and other physical infrastructure.

Now, it is facing pressure from several member countries to do so, as Poland and Lithuania have already moved ahead with plans to build high barriers of steel and razor wire.

Security on the Polish border has been reinforced, with about 15,000 soldiers deployed there along with border guards and police. Poland's Defense Ministry has activated reserves from its Territorial Defense Force to support border guards and the military by looking for migrants and helping residents whose lives have been affected by the restrictions in their area.

The ministry and police reported that groups of migrants tried to enter the country late Tuesday and early Wednesday but that all who made it in were detained.

It also accused Belarusian forces of firing shots into the air in a border area where migrants caught between the countries have set up a camp. The ministry posted video on Twitter with noises of what sounded like shots. Belarus has accused Polish forces of firing in the air.

Caught in the geopolitical standoff are thousands of migrants, including children, who have been pushed back and forth in a forested area of swamps and bogs. Eight deaths have been confirmed, and the situation gets more dangerous as temperatures have fallen below freezing at night.

Berlin said thousands of the migrants have reached Germany, where many are housed in migrant centers. Others have been detained and put in closed migrant centers in Poland and Lithuania.

Poland, which takes a harder line on migrants, has faced criticism at home and abroad for pushing many of them back into Belarus, often leaving them in the forest. Lawmakers in Warsaw recently legalized returning people to the country from which they tried to enter Poland without automatically giving them the right to apply for asylum. The Polish actions are considered illegal under international law, according to the U.N. refugee agency.

Merkel's spokesman Seibert, while blaming the "condemnable behavior of the Belarusian leader," also said the migrants deserved legal protection and humanitarian assistance—an apparent message to Poland.

Mass influxes of migrants have been gathering along Belarus’ shared borders with European Union members Poland, Lithuania and Latvia, prompting allegations that Belarusian President Alexander Lukashenko is sending them in an attempt to destabilize the bloc. Migrants stand in line to receive humanitarian aid delivered by the Belarusian Red Cross and the country's officials in a camp on the Belarusian-Polish border in the Grodno region on November 10.Ramil Nasibulin/BELTA/AFP via Getty Images