US President Joe Biden has expressed concern about the situation on the Belarusian-Polish border.
The situation is "very worrying," Biden told journalists in Washington on Friday.
"We have expressed our concern about Russia and we have expressed our concern about Belarus."
Thousands of migrants, mainly from the Middle East, are currently stuck at the EU's external border in Poland at temperatures around freezing point.
Ten people have already died in the border area in recent months, according to a report in the Polish newspaper Gazeta Wyborcza.
15,000 soldiers in the border area
The EU accuses the Belarusian ruler Alexandr Lukashenko of targeting migrants to the borders of the EU states Latvia, Lithuania and Poland in retaliation for sanctions.
At an emergency meeting of the UN Security Council on Thursday, the United States and the European members of the Belarusian government accused the Belarusian government of "orchestrating the instrumentalization of people" and destabilizing the EU's external borders.
Poland has stationed 15,000 soldiers in the area and erected a fence made of barbed wire because of the crowds.
Belarus and allied Russia announced joint military exercises in the Belarusian region of Grodno near the Polish border on Friday.
After threats of sanctions by the EU, Turkey
no longer
allows citizens of several
Arab countries to fly to Belarus from its national territory
.
The civil
aviation authority of Turkey announced on Friday that
people with Syrian, Iraqi and Yemeni passports are no longer allowed to buy tickets and board until further notice
.
According to the EU, there is also a ban on selling one-way tickets for flights from Turkey to the Belarusian capital Minsk.
Iraq also banned migrant flights to Belarus.
The move is intended to protect Iraqis from human traffickers, as the State Department announced on Friday, according to the state news agency.
Iraq has already stopped direct flights to Belarus in the dispute over the migrant crisis on the Polish-Belarusian border.
A return of migrants on the border with Poland will be coordinated with the embassies in Moscow and Warsaw.