Hundreds of Iraqis who failed to enter the EU from Belarus returned home Thursday, as US Secretary of State Antony Blinken warned that Belarus's attempt to "weaponise migration" had to stop.

Blinken's comments came as Poland detained dozens who crossed its border in a crisis the West blames on Minsk.

The European Union accuses Belarus strongman Alexander Lukashenko of luring the migrants -- mainly Iraqi Kurds -- to the border as revenge for sanctions slapped on his regime after its suppression of opposition protests last year.

"We have in place authorities to, as necessary, add to sanctions," Blinken told reporters on a visit to Nigeria.

Belarus migrant camp
Thousands of migrants, mainly from the Middle East, are camped out or staying close to the Poland-Belarus border in dire conditions aiming to cross into the European Union Photo: BELTA via AFP / Maxim GUCHEK

"This effort to weaponise migration has to stop," he added. "First and foremost, it is doing a terrible injustice to these people that it has victimised by making them pawns."

Lukashenko and his Russian ally President Vladimir Putin have rejected the accusations and criticised Poland for not taking the migrants in.

Thousands have been stuck in freezing temperatures at the border between the two countries for days.

A Polish NGO Thursday reported that it had found a Syrian couple who had lost their one-year-old child while sleeping in the forest on the border for a month.

Belarus-EU border
Map showing the border crossing points between Belarus and the three EU countries of Poland, Lithuania and Latvia. Photo: AFP / Kenan AUGEARD

Polish media say at least 11 migrants have died since the crisis began in August.

"The woman said she had lost a one-year-old child a month ago, while in the woods," the Polish Center for International Aid said on Twitter.

The president of the European Parliament, David Sassoli, called for "the inhumanity" to stop.

"It is heartbreaking seeing a child die in the cold at the EU's doorstep," he said on Twitter.

Belarus migrant camp
Aid groups say at least 11 migrants have died since the crisis began in the summer Photo: BELTA via AFP / Maxim GUCHEK

Hope for de-escalating the crisis mounted this week, with German Chancellor Angela Merkel speaking with Lukashenko twice by phone -- his first call with a Western leader since disputed presidential elections last year.

A day after the pair's second call, the first repatriation flight for migrants landed in Iraq.

The flight carried 431 people, according to Russia's Interfax news agency and the Kurdish regional spokesman.

Lukashenko's spokeswoman Natalya Eismont said on Thursday that there were about 7,000 migrants in the country.

She said Belarus will take responsibility for sending 5,000 of the migrants home if they want to go.

She alleged German Chancellor Angela Merkel would negotiate with the EU on creating the humanitarian corridor to Germany.

But Berlin denied any agreement with Lukashenko on the possibility of a humanitarian corridor.

Speaking in Warsaw, German Interior Minister Horst Seehofer dismissed the claim as "fake news."

He said Berlin "stood by" its neighbour and fellow EU member Poland in the crisis.

His Polish counterpart Mariusz Kaminski said Warsaw had warned Minsk that if the crisis "was not stabilised by Sunday", it would halt rail traffic with Belarus.

In the latest border incident, the Polish defence ministry said Belarusian forces had first carried out reconnaissance and "most likely" damaged the barbed wire fence along the border.

"Then the Belarusians forced the migrants to throw stones at Polish soldiers to distract them. The attempt to cross the border took place several hundred metres away," it said.

"Belarusian special forces led yesterday's attack," it said.

The border guard said about 500 migrants took part in the attempted crossing and 200 of them were detained after successfully entering Poland.

It said a family of five people, including three children aged between seven and nine, had been injured in the incident and were taken to hospital.

Poland's Prime Minister Mateusz Morawiecki earlier cautioned against holding direct talks with Minsk, saying it "legitimises" Lukashenko's regime.

He had previously also blamed the Kremlin for the crisis.

US President Joe Biden said he was in touch with Poland, a NATO ally, and warned Washington could follow the EU in imposing new sanctions on Belarus.

The EU and foreign ministers of the G7 global powers on Thursday called on Lukashenko's regime "to cease immediately its aggressive and exploitative campaign".

But the Polish government has warned against any agreement on the crisis that might be struck "over our heads".

A squadron of British military engineers is expected in Poland later this month to help with border repairs, Warsaw said.

French President Emmanuel Macron, meanwhile, in phone conversations with Polish counterpart Andrzej Duda and Prime Minister Morawiecki reaffirmed "the need for Europe to maintain pressure on Alexander Lukashenko" in order to "put an end to this instrumentalisation which places many people in danger".

Copyright AFP. All rights reserved.