Ukraine's President Petro Poroshenko says that armed formations in Donbas number over 40,000 people.

"The total size of the enemy force in Donbas taking into account members of illegal armed groups exceeds 40,000 people while the Russian military grouping near the state border totals over 50,000 servicemen which is almost twice as much than in July 2014," Poroshenko said on Wednesday at a session of the National Security and Defense Council.

He also accused Russia of covertly supplying Donbas with weapons, military equipment, ammunition, clothing and fuel.

Poroshenko also called for working to build up Ukraine's defense capability and form modern Armed Forces.

Speaking of the current situation in Donbas he said Ukraine fully observes the Minsk agreements. "We have convincing evidence that all sides have recognized the strict observance by Ukraine of the Minsk agreements and their constant violation by the militants," Poroshenko said.

He accused the militants in Donbas of not letting international monitors from OSCE to duly verify the withdrawal of heavy armaments. "The militants regularly shell Ukrainian positions and civilians, engage in active reconnaissance and sabotage activities, provoke armed clashes to foil the peaceful settlement of the conflict," he said.