US President George W. Bush said he was 'very pleased' at the surprise announcement, which followed seven hours of secret negotiations in Beijing.
The talks involving China, the two Koreas, Russia, the United States and Japan could restart as soon as November, Washington's chief negotiator Christopher Hill told reporters here.
North Korea reaffirmed its pledge to give up nuclear weapons in exchange for security guarantees and other concessions, and set no conditions for ending its year-long boycott of the talks, he said.
The development was immediately welcomed by South Korea, Japan, Russia and Britain, as well as the White House, and Bush said US teams would be sent to monitor the situation.
"We'll be sending teams to the region to work with our partners to make sure that the current United Nations Security Council resolution is enforced but also to make sure the talks are effective, that we achieve the result we want," he said, referring to Washington's desire for North Korea to abandon all of its nuclear weapons programs.
Hill's announcement at a hastily-arranged news conference followed seven hours of secret talks between the US negotiator and his counterparts to the six-party talks from North Korea and its closest ally China.
"We believe it will be either this coming month, November, (or) possibly December," he replied when asked when the talks would restart.
"They did not make any conditions," he added. "For us it was very important that no-one should create conditions for attending the talks."
Hill said North Korea, one of the most poorest and isolated regimes in the world, had reaffirmed the pledge it first made last year -- before the talks stalled -- to give up nuclear weapons in return for concessions.
"We all reaffirmed, including the North Koreans, our commitment to the September (2005) statement and the de-nuclearisation of the Korean peninsula," he said.
South Korea said the developments had eased tensions following the North's October 9 atomic test.
"It gives us relief," South Korea's unification ministry spokesman Yang Chang-seok told Yonhap news agency.
US National Security Council spokesman Gordon Johndroe said in Washington: "We welcome the announcement and look forward to resuming the talks soon."
Japan's top government spokesman, Chief Cabinet Secretary Yasuhisa Shiozaki, said Tokyo had been seeking the North's "prompt, unconditional return" to the multilateral process.
The Russian foreign ministry welcomed the development and Britain hailed it as "very positive".
North Korea pulled out of the talks in November last year in protest at US financial sanctions imposed against it for alleged counterfeiting and money laundering by Pyongyang.
Pyongyang had insisted it would not return until those financial sanctions were lifted.
However Hill said North Korean envoy Kim Kye-Gwan had told him on Tuesday that it was now ready to deal with that issue in the six-party forum.
"They made very clear that these were not conditions, but they wanted to hear that we would address the issue of the financial measures in the context of the talks," Hill said.
"And I said we would be prepared to create a mechanism, or working group and to address these financial issues."
He gave no indication as to why North Korea had made such a dramatic U-turn.
The Chinese foreign ministry said Beijing had initiated the secret talks here, which also included China's envoy Wu Dawei.
"The three parties engaged in a frank and deep exchange of views on continuing the six-party talks. The three parties agreed to carry out the six-party talks in the near future, at the six parties' convenience," it said in a statement on its website.
North Korea's nuclear test triggered fierce global condemnation, including from China, and led to sweeping UN sanctions.
The six-party talks began in 2003 with the intent of convincing North Korea to give up its nuclear ambitions.
On September 19 last year, the North agreed to give up its nuclear weapons in exchange for pledges of aid and security.
In that agreement, North Korea said it would renounce all nuclear weapons and programmes, return to the international Non-Proliferation Treaty and allow UN weapons inspectors back into the country.
The other countries agreed to "respect" the North's demand for peaceful nuclear energy and said Pyongyang's request to have a light-water reactor for peaceful purposes would be revisited "at an appropriate time".
Peter Beck, Northeast Asia director of the International Crisis Group, said the breakthrough was largely down to China.
"The fact they agreed to negotiations so quickly is a clear indication that China's arm-twisting has worked," he told AFP.

Copyright AFP (Agence France-Presse), 2006