A U.S. guided missile destroyer was buzzed by four Russian military aircraft last week – with one coming as close 200 yards – in incidents the Navy has deemed, “unsafe and unprofessional,” a U.S. European Command spokesman told USNI News on Tuesday.

Three incidents in which Russian aircraft made low passes occurred on Feb. 10 while USS Porter (DDG-78) was operating in international waters in the Black Sea, Capt. Danny Hernandez told USNI News.

Two Sukhoi Su-24 Fencer fighters made low-altitude, high-speed passes on the destroyer, an Ilyushin Il-38 surveillance aircraft also made a low pass and a separate Fencer made a low altitude pass on the ship, he said. The commander of Porter determined the actions were unsafe and unprofessional.

It’s unclear if the Fencers were armed.

At least one Fencer came within 200 yards of the ship, flying at 300 feet at more than 500 knots, a defense official told USNI News on Tuesday.

None of the aircraft responded to radio queries from Porter and had their transponders turned off, Hernandez said.

The destroyer had just completed the ten-day Romanian-led multinational Sea Shield 2017 exercise. Porter left the Black Sea on Feb. 11.

The Washington Free Beacon first reported the incidents on Tuesday.

While the trio of incidents was considered unsafe, the flybys were much less provocative than when USS Donald Cook (DDG-75) was buzzed by a pair of Fencers in the Baltic Sea last April.

A defense official made clear to USNI News that while the Feb. 10 met the threshold of being considered unsafe it wasn’t in the same league as the April Donald Cook incident.

Cook and Porter are two of four U.S. Navy destroyers that are forward deployed to Naval Station Rota, Spain.