North Korea images suggest missile capable of hitting all America - U.S. experts

* Missile may feature new engines, larger warhead

* Large missile puts N. Korea in elite club, analysts say (Recasts with new assessments)

By David Brunnstrom and Josh Smith

WASHINGTON/SEOUL, Nov 30 (Reuters) - Images released by North Korea on Thursday appeared to show it has succeeded in developing a missile capable of delivering a nuclear weapon anywhere in the United States and it could be only two or three tests away from being declared combat ready, U.S.-based experts said on Thursday.

North Korea released dozens of photos and a video after Wednesday's launch of the new Hwasong-15 missile, and leader Kim Jong Un declared the country had "finally realized the great historic cause of completing the state nuclear force".

U.S.-based experts, some of whom have been skeptical about past North Korean claims to have put all of the United States in range, said data from the latest test and the photos appeared to confirm North Korea has a missile of sufficient power to deliver a nuclear warhead anywhere in America.

Experts and U.S. officials say questions remain about whether it has a re-entry vehicle capable of protecting a nuclear warhead as it speeds toward its target and about the accuracy of its guidance systems.

In an analysis for the Washington-based 38 North think tank, missile expert Michael Elleman of the International Institute for Strategic Studies said the North Korean photos showed a missile considerably larger than its predecessor.

"Initial calculations indicate the new missile could deliver a moderately sized nuclear weapon to any city on the U.S. mainland," Elleman said.

Elleman said the missile was large and powerful enough to carry simple decoys or other countermeasures to challenge U.S. missile defenses.

"A handful of additional flight tests are needed to validate the Hwasong-15's performance and reliability, and likely establish the efficacy of a protection system needed to ensure the warhead survives the rigors of atmospheric re-entry," Elleman wrote.

Only two or three more tests might be needed if North Korea could accept low confidence in the missile's reliability.

Another missile expert, whose employer does not allow him to speak publicly to the media, agreed with Elleman's assessment.

"If North Korea does not make high demands on the reliability or accuracy of the missile ... two or three more tests would suffice.

"So long as North Korea can hit U.S. cities with thermonuclear warheads, they probably don't need the ability hit every city they target or target specific aim points within those cities to convince the U.S. leadership that war with North Korea would be too expensive to contemplate."