Russian armed forces are creating a “security buffer zone” along the border between Russia and Ukraine, President Vladimir Putin said Thursday.

“I have already said that a decision was made to create the necessary security buffer zone along the border. Our armed forces are currently solving this problem. Enemy firing points are being actively suppressed, the work is underway,” Putin said.

Ukrainian foreign ministry spokesperson Heorhii Tykhyi said the plan was “aggressive” and demonstrated that “Russia is the obstacle of peace efforts now.”

Thursday’s announcement was made ahead of an expected prisoner exchange between Ukraine and Russia on Friday – an outcome of last week’s face-to-face talks in Turkey, the first time the two countries have held direct talks at any level in three years.