The United States has reportedly accused a Russian fighter aircraft of performing a “safe but unprofessional” interception of its surveillance plane over the Baltic Sea.

The last time a Russian Su-27 fighter buzzed a U.S. spy plane took place in January when an EP-3 aircraft experienced a “15-degree roll and violent turbulence” over the Black Sea. Russia and NATO member states have reported numerous airspace violations by military aircraft since 2014 in Eastern Europe.

A Russian Su-27 came within 20 feet of a U.S. Navy P-8 surveillance plane while flying Tuesday in international airspace over the Baltic Sea, CNN cited two U.S. defense officials as saying.

One official described the nine-minute intercept as “safe but unprofessional.”

“U.S. Navy ships and aircraft routinely interact with military units from other countries,” said U.S. Naval Forces Europe spokesman Lt. Cdr. Zach Harrell. He declined to comment on the specific incident, CNN reported.

Although the U.S. State Department accused Russia of violating an international incidents-prevention accord during the January interception, no official statements have been given either by the State or Defense Department.