~ Under the deal, the North would get aid worth 1 million tons of heavy fuel oil and other political concessions.

TOKYO -- North Korea could shut down its nuclear reactor within three weeks and return to disarmament talks, a U.S. envoy said Saturday. Russia, meanwhile, said disputed funds have reached a North Korean account at a Russian bank, clearing a key hurdle in negotiations.

The Yongbyon plutonium-producing reactor will be shut after the U.N.'s nuclear watchdog and North Korea agree on how to monitor the process, assistant secretary of state Christopher Hill said after returning from a rare trip to the reclusive country.

"We do expect this to be soon, probably within three weeks ... though I don't want to be pinned down on precisely the date," Hill said.

The next round of nuclear negotiations could begin in early July, though the exact timing depends on scheduling by the host nation, China, he added.

"I would expect it to happen soon after shutdown begins," Hill said.

Hill's visit -- the first to North Korea by a high-ranking U.S. official since October 2002 -- came amid growing optimism that the government in Pyongyang may finally be ready to take concrete steps toward fulfilling a promise to dismantle its nuclear programs.

Last week, North Korea invited inspectors from the International Atomic Energy Agency to discuss procedures for shutting down its reactor, five years after expelling them. The U.N. inspectors are due to arrive in the North Korean capital Tuesday.

In another sign of progress, Russia's Foreign Ministry said a bank in far eastern Russia had received North Korean funds frozen at a Macau bank that had been blacklisted by the United States over allegations of money-laundering and other financial crimes.

Because of the dispute over the $25 million, North Korea missed an April deadline for shutting down its nuclear reactor under a February agreement. The funds were freed earlier this year, but only last week started to be transferred to the Russian bank.

The North used the dispute as a reason to stay away from six-nation nuclear talks for more than a year, during which it conducted its first-ever nuclear test explosion in October.

North Korea's official Korean Central News Agency struck an upbeat tone about the talks with Hill, describing them Saturday as "comprehensive and productive."

Under the deal, the North would get aid worth 1 million tons of heavy fuel oil and other political concessions after it fully disables the reactor and takes other steps toward disarmament.

KCNA said the two sides would seek a meeting in early August of foreign ministers from the six nations in the nuclear talks -- the two Koreas, China, Japan, Russia and the United States.

Hill, however, cautioned that shutting the Yongbyon reactor was only the first step.

"Shutting down the reactor won't solve all our problems, but in order to solve our problems we need to make this beginning," he said. "We really think this is the time to pick up the pace."