A senior defense official told CBS News that two recent incidents were "more aggressive than anything we've seen in some time."
The first, on April 11, involved two Russian SU24s, when the USS Donald Cook left the Polish port of Gdynia and was about 70 nautical miles from Kaliningrad in the Baltic Sea. The official said the Russian jets made 20 passes of the American ship and flew within 1,000 yards at an altitude of just 100 feet.
In the second incident on April 12, two Russian KA27 Helix helicopters flew several circles around the Donald Cook, apparently taking photos, after which two jets again made numerous close passes of the ship in what the official described as "Simulated Attack Profile."
"They were so close they created wakes in the water," the official said.