Multiple Russian military aircraft came close to a U.S. Navy destroyer in the Black Sea on Feb. 10, incidents considered “unsafe and unprofessional,” a U.S. official said on Tuesday.

There were three separate incidents involving Russian aircraft and the USS Porter, Captain Danny Hernandez, a spokesman for U.S. European Command, said. One involved two Russian Su-24 jets, another a separate Su-24, and the third involved a larger IL-38.

“USS Porter queried all aircraft and received no response,” Hernandez said.

“Such incidents are concerning because they can result in accident or miscalculation,” he added.

The incidents involving the Su-24 were considered to be unsafe and unprofessional by the commanding officer of the Porter because of their high speed and low altitude, while the IL-38 flew at an unusually low altitude, Hernandez said.

Another U.S. official, speaking on condition of anonymity, said the closest incident that day involved the lone SU-24, which came within 200 yards of the Porter at an altitude of 300 feet (91 meters).

This is not the first time interactions have taken place between Russian jets and U.S. ships.

In April 2016 two Russian warplanes flew simulated attack passes near a U.S. guided missile destroyer in the Baltic Sea. The flights by the warplanes were so close they created wake in the water.

(Reporting by Idrees Ali; Editing by James Dalgleish)