American F-16 jets intercept 4 Russian warplanes near Alaska

Two American F-16 warplanes intercepted four Russian aircraft near Alaska, the joint US-Canadian North American Aerospace Defense Command (NORAD) said Tuesday. The "routine" intercept of the Russian planes -- which included Tu-95 bomber and Su-35 fighter aircraft -- occurred Monday, NORAD said in a statement.

"Russian aircraft remained in international airspace and did not enter American or Canadian sovereign airspace," it said, adding that such Russian activity "occurs regularly and is not seen as a threat, nor is the activity seen as provocative."

The Air Defense Identification Zone, or ADIZ, is a perimeter in which air traffic is monitored beyond the border of national airspace to provide additional reaction time in case of hostile actions.

U.S. warplanes stationed in North America have seen rare offensive action this month, shooting down an alleged Chinese  spy balloon  and three unidentified objects. U.S. officials said Tuesday that intelligence officials were tracking the spy balloon that was shot down since it lifted off from the south coast of China.