POLISH BORDER FORCES said they have been attacked with stones by migrants at the border with Belarus and responded by using water cannons against them.

The Border Guard agency posted video on Twitter showing a water cannon being directed across the border at a group of migrants in a makeshift camp.

Polish police said one officer was seriously injured when the migrants threw objects. He was taken by ambulance to hospital and it is likely his skull was fractured.

The situation marks an escalation in a tense migration and political border crisis where the lives of thousands of migrants are at stake.

The border is part of the European Union’s eastern frontier, and the EU accuses the authoritarian regime of Belarusian President Alexander Lukashenko of orchestrating a migration crisis at the border to pressure the bloc.

A large number of migrants are at the border, stuck in a makeshift camp with temperatures falling to freezing at night.

Most are fleeing conflict and poverty in Syria and Iraq and hope to reach Germany or elsewhere in western Europe. To date there have been reports of 11 deaths.

Poland’s Defence Ministry said its soldiers and other border forces were attacked with stones and other objects.

The ministry also said that Belarusian forces tried to destroy fencing along the border, while the Interior Ministry posted video apparently showing migrants trying to tear down a fence.

Poland has taken a tough stance, reinforcing the border with riot police and troops, rolling out coils of razor wire and making plans to build a tall steel fence. The approach has largely met with approval from the West, with other EU countries keen to stop the arrival of another migration wave.

But Polish authorities have also been criticised for pushing migrants back across the border and not allowing them to apply for asylum.

Russian Foreign Minister Sergey Lavrov today called the actions of Polish forces “absolutely unacceptable”, claiming they “violate all conceivable norms of international humanitarian law and other agreements of the international community”.

Polish officials have often said that Russia bears some responsibility for the crisis at the border given Moscow’s alliance with Belarus. Moscow has denied responsibility.

There was no way to independently verify what was happening because a state of emergency in Poland is keeping reporters and human rights workers out of the border area. In Belarus, journalists face severe restrictions on their ability to report as well, with only a few present at the border.

Poland’s parliament is expected to take up a legislative proposal that would regulate the ability of citizens to move in the area of the border with Belarus after the state of emergency ends at the end of this month.

The state of emergency was imposed at the beginning of September as a large number of migrants from the Middle East sought to cross into Poland from Belarus.

The EU has been putting pressure on airlines to stop transporting Syrians, Iraqis and others to Belarus.