* North Korea announced suspension of nuclear enrichment
* U.N. nuclear watchdog says preparing for return to Yongbyon
* Analysts say North Korea may continue atomic work elsewhere
By Fredrik Dahl
VIENNA, March 6 (Reuters) - The United States hopes for an "early" return of U.N. nuclear inspectors to North Korea, three years after they were expelled from the Asian state, a senior U.S. official said on Tuesday.
In a surprise move, North Korea last week said it would suspend nuclear tests, long-range missile launches and enrichment of uranium at its Yongbyon nuclear facility and allow back inspectors of the U.N. International Atomic Energy Agency.
It was part of a deal with the United States that could see the eventual resumption of nuclear disarmament talks that broke down in 2008. The United States, in turn, pledged to resume food aid to the isolated and impoverished state.
Robert Wood, acting head of the U.S. mission to the IAEA, told the agency's 35-nation board that the international community will be "watching closely ... how North Korea comports itself in carrying forward with these commitments".
"Working cooperatively with the IAEA would be an important indicator of the DPRK's (North Korea's) seriousness of purpose," Wood said, according to a copy of his remarks to the closed-door meeting at agency headquarters in Vienna.
Washington has urged Pyongyang to "initiate direct contact" with the IAEA as soon as possible, he said.
The United States "look forward to smooth discussions between the Agency and the DPRK on monitoring modalities, and to the IAEA's return to Yongbyon at an early date," Wood added.
IAEA Director General Yukiya Amano on Monday said the U.N. agency was preparing for a possible return to North Korea, but was not yet in direct contact with Pyongyang.
It is unclear how much scope for inspections the IAEA will get. The North has limited their access during two previous periods when it allowed inspectors in.
Analysts say North Korea may simply continue covert atomic activity elsewhere. Members of a U.N. expert panel said last year that the secretive state most likely had several more undisclosed enrichment-related facilities.
IAEA ROLE UNCLEAR
Wood expressed hope that last week's move by Pyongyang would lead to "substantive and meaningful" denuclearisation talks.
"This would include all nuclear activities, anywhere in the DPRK, including all aspects of its uranium enrichment program and light water reactor construction activities."
The Yongbyon complex is at the heart of North Korea's plutonium weapons programme. It includes a reprocessing plant where weapons-grade material is extracted from spent fuel rods.
In late 2010, foreign experts said North Korean officials had shown them a uranium enrichment facility at Yongbyon which potentially offered a second path to making atomic bombs.
The IAEA, whose mission is to prevent the spread of nuclear weapons in the world, is believed to have a team of inspectors who are North Korea specialists and are prepared to go to the country at short notice.
North Korea expelled the IAEA a decade ago when a 1994 deal between Pyongyang and Washington unravelled.
It threw them out again in April 2009 after rejecting the intrusive inspections provided for under a 2005 aid deal with five regional powers that allowed the U.N. watchdog to return.
Peter Crail, an analyst of the Washington-based Arms Control Association, said the exact terms for the IAEA's role did not appear to be spelled out in the U.S.-North Korea agreement.
This "means the IAEA may need to play a more proactive role in reaching out to Pyongyang and spelling out just what kind of access it will need to verify that the Yongbyon enrichment plant has suspended operations," he said in an e-mail. (Editing by)