By Josh Smith, Kantaro Komiya and Hyonhee Shin

SEOUL/TOKYO (Reuters) -North Korea fired an intercontinental ballistic missile (ICBM) off its east coast on Wednesday, prompting condemnation from the U.S. as well as the leaders of South Korea and Japan who met on the sidelines of a NATO summit.

The missile flew for 74 minutes to an altitude of 6,000 km (3,728 miles) and a range of 1,000 km, Japan Chief Cabinet Secretary Hirokazu Matsuno said, in what would be the longest ever flight time for a North Korean missile.

The launch came after heated complaints from North Korea in recent days, accusing American spy planes of flying over its exclusive economic zone, condemning a recent visit to South Korea by an American nuclear-powered cruise missile submarine, and vowing to take steps in reaction.

The White House condemned the launch and said it would take all necessary measures to ensure its security and that of South Korea and Japan.

“The door has not closed on diplomacy, but Pyongyang must immediately cease its destabilising actions and instead choose diplomatic engagement,” White House National Security Council spokesperson Adam Hodge said in a statement.

U.N. Secretary-General Antonio Guterres strongly condemned the launch and called on Pyongyang to comply with resolutions banning its development of ballistic missiles and resume dialogue aimed at denuclearisation of the Korean Peninsula, U.N. spokesman Stephane Dujarric said.

South Korean President Yoon Suk Yeol, in Lithuania for the NATO summit, convened an emergency national security council meeting and promised to use the summit to call for strong international solidarity to confront such threats.

Yoon and Japanese Prime Minister Fumio Kishida held separate talks and strongly condemned the launch as a grave violation of multiple U.N. resolutions and a serious provocation that escalates tension.

Kishida said the launch threatened peace and stability in the region and beyond, and required closer cooperation between the two neighbours and with the United States.

Yoon, at an earlier meeting with Japan, Australia and New Zealand, said: “We cannot condone these provocations, and we must respond to North Korea’s reckless actions through strong responses and solidarity of the international community.”

The top military generals of the United States, Japan and South Korea gathered for a rare trilateral meeting in Hawaii just before the missile launch.

Japan said the missile landed in the sea east of the Korean peninsula and about 250 km (155 miles) west of northern Japan’s Okushiri island.

In April, North Korea test fired its first ever solid-fuel ICBM, one of around a dozen missile tests this year and Kim Dong-yup, a professor at the University of North Korean Studies in Seoul, said the latest launch could have been a second test of the solid-fuel Hwasong-18 ICBM.

Analysts believe the North’s ICBMs can fly far enough to strike targets anywhere in the United States, and that the nuclear-armed country likely has developed nuclear warheads that can fit on its missiles.

Yang Uk, a fellow at the Asan Institute for Policy Studies, said the latest test could be part of the North’s efforts to save face and retake the initiative after a failed launch of its first-ever spy satellite in May.

Pyongyang’s accusations of U.S. airspace breaches this week, which Washington and Seoul dismissed as groundless, were likely to build justification for the launch, Yang said.

Leif-Eric Easley, an international studies professor at Ewha Womans University in Seoul, said North Korea was following a pattern of staging weapons tests in time for diplomatic events such as the Yoon-Kishida summit.

With a wary eye on North Korea’s military moves and other rising challenges in the region, Yoon has moved to repair frayed ties with Japan and reduce historical disputes that have limited cooperation between the two U.S. allies.

(Reporting by Josh Smith, Soo-hyang Choi, Hyunsu Yim and Hyonhee Shin in Seoul and Tokyo bureau; Additional reporting by Rami Ayyub and David Brunnstrom in Washington and Michelle Nichols at the United Nations; writing by Elaine Lies and Hyonhee Shin; Editing by Tom Hogue, Lincoln Feast, Raju Gopalakrishnan and Sandra Maler)

Brought to you by