"The discussions continued on political and military aspects. However, it remains difficult. It is too early to talk about something positive," Russian presidential aide Vladimir Medinsky, also the head of the Russian delegation, said following the talks.

Russian negotiators brought a large set of documents, including specific agreements, but the Ukrainian side could not sign them on the spot and took all these documents back home for study, he told reporters.

"To be honest, our expectations from the talks were not met. But we hope that next time we will be able to take a more significant step forward," Medinsky said after the meeting, which lasted nearly three hours at the Belovezhskaya Pushcha on the Belarus-Poland border.

Both sides addressed the issue of civilian evacuation, and the Ukrainian side assured Russia that the humanitarian corridors will start working on Tuesday, he said.

"There was some positive progress when it comes to improving the logistics of humanitarian corridors," Mykhailo Podoliak, advisor to the Head of the President's Office of Ukraine, tweeted after the negotiations.

"Today there were no results that would significantly improve the situation. Nevertheless, I emphasize once again that the consultations will continue," Podoliak said in a video message posted on Twitter.