US Closes Airspace In Northern Alaska, Defines It As National Defense Airspace

The US Federal Aviation Administration closed some airspace in northern Alaska and declared it "national defense airspace," a Notice to Airmen (NOTAM) stated on Friday as the Pentagon was downing an unidentified object over the territory.

"Pursuant to 49 USC 40103(b)(3), the federal aviation administration (FAA) classifies the airspace defined in this NOTAM as 'ntl defense airspace'. pilots who do not adhere to the following proc may be intercepted, detained and interviewed by law enforcement," the notice said.

It also warned that the US government could "use deadly force" against any aircraft that are determined to pose a security threat.

The flight restrictions came as the US shot down a high-altitude object over Alaska on Friday afternoon, according to White House National Security spokesman John Kirby.