Hours after Russia said North Korea had accepted a US proposal for six-way talks, and President George W. Bush spoke to Chinese President Hu Jintao on the issue, the State Department said it was "very encouraged" by developments.

"At this moment we have indications that we find very encouraging," said State Department spokesman Boucher said.

Russia's foreign ministry said earlier that North Korea had agreed to a US proposal to hold six-nation talks to try to resolve the nuclear standoff.

Should the statement be borne out, it would be seen as a diplomatic victory for Washington, which has consistently refused Pyongyang's demands for one-on-one talks on the crisis that erupted in October.

Boucher said that US diplomats had not yet consulted Russian opposite numbers on the announcement, and officials said US optimism was based on Bush's call on Wednesday with Hu.

"We are actually beginning to make serious progress about sharing responsibility on this issue," Bush said in a White House news conference on Wednesday.

His administration has long argued that previous bilateral talks with North Korea have failed, so the current nuclear crisis should be addressed by key Asian regional powers.

In an earlier compromise, US, Chinese and North Korean officials sat down in Beijing in inconclusive three-party talks in April.

North Korea has been considering a new US proposal for resuming three-party negotiations followed quickly by six-party talks, with Seoul, Tokyo and Moscow joining the forum.

A senior US official said on condition of anonymity that it was hoped new talks could take place before September, and that it might not be necessary to reconvene a three-way dialogue first.

The US proposal was submitted to North Korea by China following Chinese Deputy Foreign Minister Dai Bingguo's return last week from a trip to Washington.

Beijing dispatched Dai to Pyongyang earlier this month for talks with reclusive leader Kim Jong-Il and then sent him on to Washington for talks with Secretary of State Colin Powell and top White House officials.

North Korea on Wednesday, in public at least, reverted to its insistence on a non-aggression pact and one-on-one talks, which Washington has ruled out.

"It is the stand of the DPRK (North Korea) that the bilateral talks should be held between the DPRK and the US to be followed by the US-proposed multilateral talks in order to settle the nuclear issue between Pyongyang and Washington," Pyongyang's official Korean Central News Agency said.

The dispatch dismissed as "unacceptable" Washington's demand that North Korea scrap its nuclear weapons ambitions prior to substantive dialogue and reiterated North Korea's own demand for a non-aggression pact.

The nuclear crisis was triggered in October when Washington revealed that Pyongyang was running a nuclear programme in violation of a 1994 arms control accord.

North Korea kicked out UN nuclear inspectors late last year and then withdrew from the Nuclear Non-Proliferation Treaty. It has since claimed it has reprocessed 8,000 spent nuclear fuel rods after reopening its nuclear complex at Yongbyon, north of Pyongyang, frozen under the 1994 accord.

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