On Saturday, two pairs of Russian Tupolev Tu-95 bombers approached the US West Coast, causing the Air Force to scramble to intercept the planes before they breached US airspace, two senior defense officials told Fox News.

The first incident reportedly occurred at 10:30 a.m. ET off the coast of Alaska, when Norad identified the Russian planes and two F-22s hurried to intercept them. Another incident occurred at 11 a.m. ET off the coast of central California and was responded to by two F-15s.

The Russian bombers they intercepted are capable of carrying nuclear weapons, but sources do not indicate whether they were armed.

The Air Force intercepted the bombers before they entered America's sovereign air space, which extends 12 miles out from the coast, but the presence of the bombers is an ominous sign during the heightened tensions between Russia and the US.

As retired Air Force Lt. Gen. Thomas McInerney, who formerly commanded the North American Aerospace Defense Command (Norad) told The Washington Free Beacon: "It's becoming very obvious that Putin is testing Obama and his national-security team."

The type of warfare being teased is reminiscent of the Cold War not only in theory, but in practice.

"These long-range aviation excursions are duplicating exercises I experienced during the height of the Cold War when I commanded the Alaska Norad region," McInerney told The Free Beacon.

The Tupolev Tu-95. Parfaits via Wikimedia Commons

Pentagon officials haven't given the exact location of the interceptions, but ABC News cites one official as saying it could have taken place as "far out as 200 miles."

The Pentagon's John Kirby told The Free Beacon that the US assessed the flight of the Russian bombers as another training activity.

Since the start of the crisis in Ukraine, Russia has flown increasingly aggressive aircraft missions throughout Europe and the Pacific. From May 2014 to September 2014, the US intercepted Russian bombers over Guam and off the coast of California and Alaska. In September, two Russian aircraft carried out a mock cruise-missile attack on the US.

Throughout 2014, the European Leadership Network estimated that Russia and the West had up to 40 military encounters. Among these, three were designated as high-risk incidents that could have led to casualties or a military confrontation.

In April, Adm. Bill Gortney, the general at the head of Norad, told reporters that Russia was using its long-range bomber fleet to "message" the US about Moscow's international military capabilities.

"They are messaging us. They are messaging us that they are a global power," Gortney said, noting that the US did "the same sort of thing" to Russia in Europe.