The Russian Air Force scrambled MiG-31 jet fighter to intercept a U.S. Air Force RC-135 spy plane over the Bering Sea on Friday, the Defense Ministry’s National Defense Control Center said.

The U.S. Air Force RC-135 aircraft flew airspace around over the neutral waters of the Bering Sea approaching the Russian state border on December 11. The spy plane stayed in international airspace.

A MiG-31 fighter from the Pacific Fleet’s air defense quick reaction alert forces was scrambled to prevent the violation of the state border, the National Defense Control Center said. “The Russian fighter’s crew identified the air target as a U.S. Air Force RC-135 strategic reconnaissance aircraft and escorted it,” the Center said.

After the foreign spy plane flew away from the Russian state border, the MiG-31 fighter safely returned to its home base, the statement says. “The Russian fighter’s flight proceeded in strict compliance with the international rules of using the airspace,” the National Defense Control Center said. The U.S. aircraft was not allowed to violate the Russian state border, it stressed.