Ukraine‘s armed forces on Saturday said joint military drills with NATO troops would begin in a few months’ time, a step that could stoke tensions with Moscow which has expressed its opposition to such a move.

NATO voiced concern on Thursday over what it said was a big Russian military build-up near eastern Ukraine after Russia warned that a serious escalation in the conflict in Ukraine‘s Donbass region could “destroy” Ukraine.

The Kremlin on Friday said that any deployment of NATO troops to Ukraine would lead to further tensions near Russia’s borders and force Moscow to take extra measures to ensure its own security.

Ukrainian troops have battled Russian-backed separatist forces in the eastern Donbass region in a conflict Kyiv estimates has killed 14,000 people since 2014.

The drills will involve more than 1,000 military personnel from at least 5 NATO member states and will be held in a few months, the Ukrainian armed forces said in a statement on Facebook on Saturday.

“In particular, defensive actions will be worked out, followed by an offensive in order to restore the state border and territorial integrity of a state that has been subjected to aggression by one of the hostile neighbouring countries,” the statement said.

It did not specify exactly when the drills would take place.