North Korea's new leaders, hungry for food aid ahead of a landmark anniversary, have bought time in a deal with Washington but show no sign of actually renouncing their nuclear bargaining chip, experts say.

Under the deal announced Wednesday, the communist state now led by the young and untested Kim Jong-Un agreed to suspend nuclear and long-range missile tests, and its uranium enrichment programme.

The United States -- which analysts said was keen to remove at least one strategic headache in an election year -- agreed in return to provide North Korea with 240,000 tonnes of desperately needed food.

Implementation will be the key, however, after almost two decades of nuclear negotiations and broken agreements amid mutual accusations of bad faith.

Peter Beck, Korea representative of the Asia Foundation, likened the deal to "a second marriage -- the triumph of hope over experience", but also said that pragmatism had prevailed in Washington and Pyongyang.

"At this point the best that can be done is to freeze the nuclear programme," he told AFP.

North Korea under Jong-Un's late father Kim Jong-Il repeatedly offered to bargain over its nuclear programme, only to renounce negotiations and press ahead with atomic and missile tests once new aid was secured.

But for now at least, the deal appears to be the best that could be hoped for by both sides as US President Barack Obama grapples for re-election and North Korea prepares to mark a symbolic date next month.

"For the United States, the agreement lays the foundation for bringing the North's nuclear issue under control for a while," professor Yang Moo-Jin of Seoul's University of North Korean Studies told AFP.

Obama needs some progress on North Korea at least before facing US voters in November, especially when Iran and Syria present such challenges, Yang said.

"For Jong-Un, he secured a practical gain in the form of food aid."

Yang said Kim Jong-Un needed massive food aid in the run-up to April 15, the 100th anniversary of the birth of his grandfather and North Korea's founding leader Kim Il-Sung.

The regime has pledged to turn the impoverished nation, stalked by years of famine, into a "strong and prosperous" state to mark the anniversary.

Officially at least, Pyongyang and Washington are committed to a six-nation agreement of September 2005, under which the North would scrap all nuclear programmes in return for major diplomatic, security and economic benefits.

But many analysts doubt whether the regime will ever abandon a decades-old atomic drive that is vaunted as one of the Kim's dynasty's greatest achievements.

"For now, the agreement is a welcome development. Talking is better than not talking and a freeze is better than an unfettered nuclear programme," Beck said.

But he added that the North would not give up its nuclear programmes and it was "highly unlikely" that any significant progress could be made on denuclearisation any time soon.

North Korea abandoned the six-nation talks in April 2009 and conducted its second nuclear test the following month.

There have been months of diplomatic effort to revive them, culminating in US-North Korean talks in Beijing last week that agreed the latest deal.

Yang said that if things go as planned, six-party negotiations may resume in the first half of this year.

Richard Bush, a senior researcher at the US Brookings Institution, said Wednesday's agreement could be an initial step towards serious negotiations.

"Or they could simply be a ploy to get nutritional assistance and meddle in South Korean politics," Yonhap news agency quoted him as saying.

"North Korea's record suggests the latter, but we shall see."

The North bitterly opposes the South's conservative government, which faces its own elections this year.

While there is plenty of scepticism about the latest nuclear deal, it has raised some hopes of better relations under Kim Jong-Un, whose personality and policies remain a closed book to the outside world.

Stephan Haggard and Marcus Noland of the Peterson Institute for International Economics said there were questions after Kim Jong-Il's death in December about whether anyone was in charge in Pyongyang.

"Now we know that someone is capable of making decisions and their first one constitutes a conciliatory (indeed, concessionary), not belligerent gesture," they wrote in the blog Witness to Transformation.

"The agreement does not completely freeze the North Korean nuclear programme, but it is progress."

Key developments in N. Korea nuclear standoff
Seoul (AFP) March 1, 2012 - North Korea has announced it will suspend nuclear and missile tests and its uranium enrichment programme as part of a deal that includes US food aid.

Here are key dates since the latest nuclear standoff erupted:

2002

- October: The US says North Korea is running a secret highly enriched uranium programme in violation of a 1994 denuclearisation accord -- a charge it denies. Oil shipments under the 1994 pact are suspended.

- December: The North unseals its plutonium-producing Yongbyon reactor for the first time since 1994 and expels inspectors from the International Atomic Energy Agency (IAEA).

2003

- January 10: North Korea says it will quit the nuclear Non-Proliferation Treaty.

- August 27-29: First round of six-party disarmament talks -- involving the two Koreas, China, Japan, Russia and the United States -- is held in Beijing.

2005

- February 10: North Korea declares it has manufactured nuclear weapons for self-defence.

- September 19: At six-party talks, North Korea agrees to scrap its nuclear programme and return to the Non-Proliferation Treaty in return for security and diplomatic guarantees and energy aid.

- November 9-11: New round of talks collapses, with the North insisting that US-led financial sanctions which froze its accounts in a Macau bank be lifted.

2006

- October 9: North Korea tests a nuclear weapon.

- October 31: Following secret talks with his North Korean counterpart, US negotiator Christopher Hill announces the North has agreed to return to the six-party talks.

2007

- February 13: China announces deal under which North Korea will disable nuclear plants at Yongbyon and allow IAEA inspectors to return. In exchange it will get one million tonnes of fuel aid and be removed from a US list of terrorist states.

- July 14: First shipment of fuel aid reaches North Korea, along with IAEA inspectors. US says Yongbyon has been shut down.

- October 3: Six nations announce deal under which the North will declare all nuclear programmes and disable Yongbyon by the end of 2007. Disablement starts in November.

2008

- June 26: North Korea hands over declaration on its nuclear programme.

- August 26: North Korea says it has stopped disablement and will consider restoring the plants in protest at US failure to drop it from the terrorism blacklist.

- October 11: US says it is removing North Korea from its list of state sponsors of terrorism.

- December 8-11: Six-party talks end in stalemate after failing to agree on how to verify the North's declaration.

2009

- April 5: North Korea launches long-range rocket which it says put a communications satellite into orbit. The United States says the launch was actually a missile test.

- April 13: UN Security Council unanimously condemns North Korea for the launch and tighten existing sanctions.

- April 14: North Korea announces it will quit the six-nation talks, reopen disabled plants and strengthen its nuclear deterrent.

- May 25: North carries out a second nuclear test.

-June 12: UN Security Council passes resolution enforcing new sanctions.

2010

- November 12: North unveils uranium enrichment plant to visiting US scientists. Experts say it could be reconfigured to make atomic weapons.

2011

- July 22: North and South Korean nuclear envoys meet in Bali to discuss possible resumption of six-party talks.

- July 28-29: US and North Korea hold similar talks in New York, meet again in Geneva in October.

- December 17: North Korean leader Kim Jong-Il dies and is succeeded by his youngest son Kim Jong-Un.

2012

- February 23-24: US and North Korea hold third round of bilateral talks.

- February 29: North says it will suspend nuclear and missile tests and its uranium enrichment programme.