In a deal with the United States, North Korea has agreed to a moratorium on nuclear enrichment and testing in exchange for food aid.
The announcement follows sit-down negotiations between the US and North Korea last week in Beijing.
In return for 240,000 tonnes of food aid, Pyongyang has agreed to suspend uranium enrichment and long-range missile tests, and allow United Nations inspectors to monitor the Yongbyon reactor.
North Korea says the US is also holding out the possibility of lifting sanctions once formal disarmament talks resume.
The UN nuclear watchdog is calling it an important step forward, but US secretary of state Hillary Clinton has been more cautious in her response.
"Today's announcement represents a modest first step in the right direction," she said.
The two sides were believed to be close to a food exchange deal back in December before the death of Kim Jong-Il.
The fresh development paves the way for a possible resumption of the six-party disarmament talks that North Korea abandoned three years ago.
But US officials like White House spokesman Jay Carney remain sceptical of Pyongyang's commitment.
"The agreement that the North Koreans have made [is] very welcome but obviously they need to be followed up by actions," he said.
"Commitments to do something are one thing, actually doing them are another."
The deal is also a boost to America's efforts to rein in renegade nuclear programs around the world and comes as the Obama administration intensifies pressure on Iran over its nuclear ambitions.
Patrick Cronin, a senior director at the Centre for a New American Security in Washington, says Iran will be watching what happens in North Korea closely.
"What it does mean to Iran is that now there are no other distractions at least on the nuclear proliferation front so that the international community can focus on Iran," he said.
"I would expect that could increase the chances of some kind of a dialogue but whether that dialogue really has traction, whether it really is serious, those are much harder judgements to make that this point."