American and Russian fighter jets will take turns pursuing a civilian plane across the Pacific next week in a landmark exercise to test their response to a potential international hijacking.

Aircraft and officers from Russia and the North American Aerospace Defence Command, a joint US-Canadian agency, will track the civilian plane, an executive-style jet that will play the role of a hijacked civilian airliner.

Vigilant Eagle, the three-day exercise due to start in Alaska, is the first of its kind to test how well the two forces can hand off responsibility for the "hijacked" plane.Both countries' civil air traffic control agencies are also taking part.

Officials on both sides of the trust-building military exercise chose a mutual, modern-day interest - the fight against terror - to create an incident that could entangle the two countries.

"We try to anticipate any potential areas in which it might be necessary for us to launch fighter jets," said Major Michael Humphreys, a NORAD spokesman. A terrorist hijacking, he said, "is every bit as probable as any other" scenario.