While the United States celebrated Independence Day, two pairs of Russian bombers flew off the coast of California and Alaska -- forcing the Air Force to scramble fighter jets to intercept both flights, two senior defense officials tell Fox News. 

The first incident occurred at 10:30 a.m. ET on July 4 off the coast of Alaska, Fox News is told. Two U.S. Air Force F-22 jets were scrambled from their base in Alaska to intercept two Tupolev Tu-95 long-range strategic bombers, capable of carrying nuclear weapons. 

The second incident occurred at 11:00 a.m. ET also on July 4, off the central coast of California. Two F-15s from an undisclosed location were scrambled to intercept another pair of Tu-95 Bear bombers. 

A spokesman for NORAD would not confirm if either pair of bombers was armed. 

At no time did either pair of bombers enter U.S. airspace, 12 nautical miles off the coast, according to one defense official. Neither official would reveal just how close the bombers came to U.S. shores. 

At the same time the bombers were in the air probing the West Coast of the United States, Russian President Vladimir Putin called President Obama to wish him a happy July 4th. 

"These are not unprecedented flights, but we are postured to respond whether Alaska or California," NORAD spokesman Michael Kucharek said. "At no time did the bombers enter North American sovereign airspace." 

A similar incident took place on July 4, 2013.  

Lucas Tomlinson is the Pentagon and State Department producer for Fox News Channel. You can follow him on Twitter: @LucasFoxNews