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 told reporters after briefing his Japanese counterpart, Kenichiro Sasae, on the outcome of his two-day surprise trip to Pyongyang.