Russian and Chinese nuclear-capable strategic bombers patrolled near the U.S. state of Alaska in the North Pacific and Arctic on Thursday, the two countries said, a move that prompted the United States and Canada to scramble fighter jets.

Russian Tu-95MS “Bear” strategic bombers and Chinese Xi’an H-6 strategic bombers took part in patrols over the Chukchi and Bering seas and the North Pacific, Russia’s defense ministry said.

“During the flight, Russian and Chinese crews cooperated in the new area of joint operations during all stages of the air patrol,” the Russian ministry said in a statement.

“At some stages of the route, the air group was accompanied by fighters from foreign countries,” it said.

On the five-hour flight, the Russian and Chinese bombers were escorted by Russian Sukhoi Su-30SM and Su-35S fighters. No foreign airspace was violated, Russia said.

The U.S. military’s North American Aerospace Defense Command (NORAD) said that U.S. and Canadian fighter jets had intercepted the Russian and People’s Republic of China (PRC) aircraft in the Alaska Air Defense Identification Zone (ADIZ).

“The Russian and PRC aircraft remained in international airspace and did not enter American or Canadian sovereign airspace,” NORAD said.

“This Russian and PRC activity in the Alaska ADIZ is not seen as a threat, and NORAD will continue to monitor competitor activity near North America and meet presence with presence.”

The joint patrol had deepened strategic mutual trust and coordination between the two militaries, a spokesperson for China’s defense ministry said.

It had “nothing to do with the current international situation”, said Zhang Xiaogang.

“The event was held as part of the implementation of the military cooperation plan for 2024 and is not directed against third countries,” Russia said.