The Navy ship buzzed earlier this week in the Baltic Sea by Russian jets could have opened fire under US rules, Secretary of State John Kerry said Thursday.

The destroyer USS Donald Cook was sailing in international waters about 70 nautical miles from the Russian exclave of Kaliningrad when it reported that pairs of Russian Su-24 jets made several close-range passes on Monday and Tuesday. The planes were apparently unarmed, but on at least one occasion one of the jets came within an estimated 30 feet (9 meters) of the Cook.

"We condemn this kind of behavior. It is reckless. It is provocative. It is dangerous. And under the rules of engagement that could have been a shoot-down," Kerry said in an interview with CNN Espanol and the "Miami Herald."

"People need to understand that this is serious business and the United States is not going to be intimidated on the high seas. ... We are communicating to the Russians how dangerous this is and our hope is that this will never be repeated."

The US military's Europe Command (EUCOM) had earlier published several videos allegedly showing the maneuvers by the Russian jets.

"The Russian aircraft flew in a simulated attack profile and failed to respond to repeated safety advisories in both English and Russian," EUCOM said.

A US defense official said the flyovers constituted one of the most aggressive interactions between the two former Cold War adversaries in recent memory, and that the repeated flights by the jets were so close they created wake in the water. A Russian KA-27 Helix helicopter also made passes around the Cook, taking pictures.

Moscow rejects criticism

Meanwhile, Russia's Defense Ministry has rejected US complaints about the flights over the destroyer.

Major General Igor Konashenkov, spokesman for the Defense Ministry, said Thursday that the pilots of Russian Su-24 jets saw the ship and turned back "while using all measures of precaution."

"The reason for such an aggrieved reaction from our US colleagues is, frankly speaking, incomprehensible to us," he said.

State Department spokesman John Kirby said he will bring up the issue with Russian Foreign Minister Sergey Lavrov.

White House spokesman Josh Earnest told reporters at a daily press briefing that Washington had raised its concerns with Russian officials.

"I can tell you that communication has occurred, and we'll seek to resolve our differences through well-established military channels," he said.

The incident comes amid military tensions between NATO and Moscow, prompted by the outbreak of the Ukraine conflict in 2014. NATO is currently planning its largest military buildup in the Baltic and Poland since the Cold War.