WARSAW, Poland (AP) — Polish forces at the border with Belarus used a water cannon yesterday against stone-throwing migrants, as Warsaw accused Belarusian authorities of giving smoke grenades and other weapons to those trying to cross the frontier.

The events marked an escalation in the tense crisis on the European Union’s eastern border, where the West has accused President Alexander Lukashenko of using the migrants as pawns to destabilise the 27-nation bloc in retaliation for its sanctions on his authoritarian regime. Belarus denies orchestrating the crisis.

The Poland Border Guard agency posted video on Twitter showing a water cannon being directed across the border at a group of migrants who appeared to be throwing objects. Polish authorities said nine of its forces were injured — seven policemen, one soldier and a female border guard.

Some 2,000 migrants were at the frontier in makeshift camps in the freezing weather, but only about 100 were believed to be involved in attacking the Polish forces at the crossing near Kuznica, said Border Guard spokeswoman Anna Michalska. The crossing has been closed to all traffic since last week.

Police spokesman Mariusz Ciarka later said the migrants at the crossing had been “pacified”. He added that the attackers had been given smoke grenades by the Belarusians and threw stones at the Polish police, with the entire operation monitored by the Belarusian services using a drone.

The Belarus State Border Guard Committee and the Belarusian Foreign Ministry both said they would investigate Poland’s actions.

“These are considered violent actions against individuals who are on the territory of another country,” committee spokesman Anton Bychkovsky was quoted as saying by Belarus’ State news agency Belta.

Lukashenko also again rejected accusations of engineering the crisis and said his Government has deported about 5,000 illegal migrants from Belarus this fall.

“We’re not collecting refugees all over the world and bringing them to Belarus, as Poland has informed the European Union. Those who come to Belarus legally, we accept here, the same way any other country would. Those who violate the law, even in the slightest, [we put] on a plane and send back [home],” he told a Government meeting dedicated to the situation at the border.

In May, however, he had railed against the EU sanctions imposed on his country for its harsh crackdown on internal dissent, saying: “We were stopping migrants and drugs — now you will catch them and eat them yourself.”

At yesterday’s meeting, Lukashenko said he and German Chancellor Angela Merkel agreed Monday by phone that neither Belarus, nor the EU would benefit from an escalation of the border situation. He said he proposed a resolution but did not say what it was, adding that Merkel is discussing his proposal with other EU leaders.

Some of the migrants have children with them at the border in their desperate bid to reach the EU. Most are fleeing conflict, poverty and instability in the Middle East and elsewhere. At least 11 deaths have been reported in recent weeks as the weather has turned colder and they are trapped in the dank forest between the forces of the two countries.

While some have managed to get into the EU before Poland, Lithuania and Latvia bolstered their borders, passage appears to be much harder now.

Poland’s Defence Ministry said Belarusian forces tried to destroy border fences, and its interior ministry posted video apparently showing migrants trying to tear one down. It said the migrants are using the smoke grenades and similar weapons given to them by Belarusian troops who no longer seem to be trying to conceal their involvement.

Poland has taken a tough stand against the migrants’ illegal entry, reinforcing the border with riot police and troops, rolling out razor wire, and making plans to build a tall steel barrier. The Polish approach has largely met with approval from other EU nations, who want to stop another wave of migration.

But Poland also has been criticised by human rights groups and others for pushing migrants back into Belarus and not allowing them to apply for asylum.

Russian Foreign Minister Sergey Lavrov called Poland’s actions “absolutely unacceptable”, saying they “violate all conceivable norms of international humanitarian law and other agreements of the international community”.

Warsaw also said Moscow bears some responsibility for the border crisis, given its strong support for Belarus. The Russian Government has denied responsibility.

Events at the border have been difficult to verify independently. Poland has imposed a state of emergency, which bars reporters and human rights workers from the area. In Belarus, journalists face severe restrictions on their ability to report.