Japan says it could shoot down a North Korean missile

Japan says it could shoot down missiles for its U.S. ally if North Korea fires them at Guam.  

Defence Minister Itsunori Onodera told Thursday's parliamentary session that a missile attack on the U.S. territory would breach the U.S. deterrence against an attack on Japan. He said that would be a Japanese national emergency because it would threaten Japan's existence as a nation.

He said Japan in that case can exercise the right to "collective'' self-defence and activate the Aegis destroyer ship-to-air missile defence system.

Onodera's comment underscores Japan's growing military role and reverses its previous position that it can only shoot down missiles headed to Japan.  A defence law that took effect last year allows Japan's military, limited by the country's constitution to acting only in self-defence, to also defend U.S. and other allies when they come under enemy attack.