President of Ukraine Petro Poroshenko has said that presence of the Russian troops in Ukraine has been proven, and at different times the number of Russian troops varies from between 4,000 to 14,000.

"The fact of the presence of Russian soldiers in our territory was proven many times, and in various times there are from 4,000 to up to 14,000 Russia regular troops in the territory of Ukraine," he said at a joint conference with Slovak President Andrej Kiska in Kyiv on Wednesday.

"This is not just Ukrainian information, this is the data of NATO intelligence and other sources, we have the facts of [Russian soldiers] crossing of our border, which was registered by satellite," Poroshenko said.

He said this concerns not just the number of Russian troops, but also a significant number of modern weapons, "including missiles and anti-aircraft complexes."

"In order for there to be a peace, we need to implement the Minsk agreements. In particular, the item which stresses the necessity to shut down a part of Russia-Ukraine border, control of which was lost by Ukraine, and withdrawal of Russian troops from our territory," he said.

"It would be very important if the Russian troops grab all Russian military equipment: tanks, missiles, aircraft complexes, modern radio electric complexes, the most updated weaponry samples, which are challenged today on the Ukrainian people," Poroshenko added.

He said that the Russian authorities regularly state that supplies of lethal weapons to Ukraine will worsen tensions in the region, while Russia itself supplies modern weapons to its troops and to the militants it controls every day.