Two long-range Russian bombers flew within 50 miles of the northern California coast Monday, but stayed out of U.S. airspace, a defense official said today.

The incident began much further north when four Russian Tu-95 Bear bomber planes and a refueling tanker enter the outer Air Defense Identification Zone (ADIZ) near Alaska. The ADIZ extends for 200 miles and is considered international airspace, but if military aircraft enter the ADIZ, then the U.S. NORAD sends fighter jets to get a visual identification, NORAD spokesperson Capt. Jennifer Stadnyk said.

That's what happened Monday afternoon when two American F-22 Raptor fighter jets went up to keep an eye on the Russian aircraft.

At some point the bombers left the ADIZ - two headed west back towards Russia and the other two headed south. Those heading south once again entered the ADIZ off the northern California coast. This time they were picked up visually by a pair of American F-15 fighters.

Officials said that at no time did any of the aircraft enter U.S. airspace. There were no communications with the Russian aircraft. The incident was first reported by The Washington Free Beacon.

Stadnyk said that the last five years there have been 50 intercepts of Russian military aircraft entering North American ADIZs. One of the new stealth F-22 Raptors' first missions reportedly was such an interception back in 2007.

The last time the Russian bombers came close to the California coast was July 4, 2012.