"Over the last few weeks the process of the release of prisoners has been very fragile," Tandyt said.

"On Monday, we released 16 Ukrainian soldiers from the militants’ captivity. Some of them have already met with their relatives," he said.

"We thanked the Donetsk authorities when they released 16 people as a sign of goodwill. We are also preparing a reciprocal gesture. And I hope that the process will continue.

"As of today, we have released more than 2,500 of our soldiers. At least 400 people are still in captivity.”