The U.S. Air Force reported to have intercepted six Russian military planes to the west of Alaska. This is mentioned in the NORAD's (North American Aerospace Defense Command) official statement on the incident, as Voice of America quoted it.
'Two pairs of F-22s and an E-3 Airborne Early Warning and Control System from North American Aerospace Defense Command positively identified and intercepted a total of four Tupolev Tu-95 bombers and two Su-35 fighters entering the Alaskan Air Defense Identification Zone (ADIZ) on May 20. Specifically, two of the Russian bombers were intercepted by two F-22s, and a second group of bombers with Su-35 fighters was intercepted later by two additional F-22s, while the E-3 provided overall surveillance. The Russian bombers and fighters remained in the international airspace and at no time did the aircraft enter United States or Canadian sovereign airspace', reads the message.
The operation began as soon as the Russian planes were spotted by the AA defense system in deployed in Alaska; the American fighters ceased to escort them when they left the area adjacent to the U.S. airspace.
A number of similar incidents have taken place over the last few years.