BRUSSELS 

NATO Secretary-General Jens Stoltenberg on Tuesday reassured Poland of the alliance’s solidarity amid the escalating migration crisis at its border with Belarus.

“Belarus using migrants as (a) hybrid tactic is unacceptable,” Stoltenberg wrote on Twitter following his phone conversation with Polish President Andrzej Duda.

“NATO stands in solidarity with Poland and all our allies in the region,” he added.

On Monday, Polish authorities stepped up border protection and mobilized over 12,000 troops after a large group of migrants started marching towards the country’s frontier with Belarus, accompanied by the Belarusian military.

In an interview with public broadcaster Polish Radio, Poland’s Deputy Foreign Minister Piotr Wawrzyk alleged that the Belarusian government is trying “to cause a major incident, preferably with shots fired and casualties.”

“The Belarusian regime is keeping up its provocations and resorting to the worst possible tactics,” he added.

Poland and the EU have accused Belarusian President Alexander Lukashenko of seeking revenge for the bloc’s sanctions on his regime by inviting “tourists” from countries that are the main sources of migration to the EU.

Both NATO and EU consider the Belarusian government’s approach towards migrants as a hybrid threat meant to destabilize and undermine security in European countries through non-military means.

According to estimates from last month, over 6,000 migrants, mostly from Iraq, Afghanistan, and Syria, tried to enter the EU via the Belarus-EU border, up sharply from last year’s 150.​​​​​​​