Luik said that Russian warships harass NATO vessels by following them or passing by them at close range. He also mentioned low-altitude maneuvers conducted over NATO shipsby Russian aircraft.

"This is happening in international waters," the Estonian minister pointed out. "It is a violation of best maritime practices."

Luik explained that such incidents occur primarily in connection with U.S. vessels, but with other allied vessels as well.

The minister also noted the deployment of Russian weapons in the Baltic Sea region and positioning of Iskander and S-400 missile systems in the Russian exclave of Kaliningrad. "Extensive equipping is underway," he observed. "It is completely unwarranted and is a sign of aggressiveness in our region."

According to Luik, Russia is backing up the equipping with a system of troop relocation. "Russia has developed a high-level system for the relocation of troops, which means that units which are on the Ukrainian border today may be on the border of the Baltic countries tomorrow," he said.