Ukrainian President Petro Poroshenko has said that the presence of NATO ships in the Black Sea should be increased due to Russia's aggression, the press service of the head of state has reported.

Poroshenko noted the need to increase the presence of the warships of NATO in the Black Sea given Russia's aggressive actions in the Black Sea and the Sea of Azov and the seizure of Ukrainian ships and seamen.

"We should increase the NATO presence in the Black Sea," the president said. He said that "after the illegal annexation of Crimea, it was completely ruined the balance in the Black Sea."

"[Russian President Vladimir] Putin uses the land of Crimea for placing missiles there, for significantly increasing the Black Sea fleet. This creates an extremely big danger for the destabilization," the head of state said.

He did not rule out further possible aggressive actions of Russia in the Black Sea, as it was with the attack on Ukrainian military boats.

"That is why the navy presence of NATO, it would be a factor of stabilization," he said.

The President of Ukraine also said that the world coalition should speak from the position of strength with the Russian president. If the global coalition would be strong enough, if sanctions, which are extremely efficient, will work, if all instruments of pressure which have… this conversation [with Putin] can be efficient," Poroshenko said.