"I am hopeful that we can get to six-party talks of some kind in early July," Hill told reporters in Japan on the final leg of a tour that included stops in China and South Korea, all parties to the negotiations.

"Obviously, we want to move ahead on the issue of denuclearisation," he said.

"I think you will see a lot of bilateral meetings in the coming few days, a lot of efforts to try to coordinate as we try to regain the momentum and make up for the lost time," he said.

The comment came after he said that frozen funds which had been at the heart of a long-running row that had stalled disarmament talks were finally handed back to North Korea through a bank account in Moscow.

North Korea has refused to shut down its Yongbyon reactor, as it promised under a six-nation deal reached in February, until it received the cash.

Shutting down Yongbyon, the source of raw material for bomb-making plutonium, is part of the initial action to be taken under the deal, with North Korea to receive badly needed fuel aid as a reward.

"We have had considerable discussions about the initial phase. We are confident that the initial phase will begin to be implemented in, literally, in days ahead," Hill said.

In the second stage of the six-way deal, Pyongyang is supposed to permanently disable the reactor and all other atomic programmes.

"The purpose would be to focus on the next phase," Hill said of the upcoming round of talks.

But he and his Japanese counterpart Kenichiro Sasae both hinted the next talks may not be another formal round in Beijing. Hill talked of convening six-way talks "of some kind."