North Korea has agreed to shut down its Yongbyon nuclear reactor within three weeks, US nuclear envoy Christopher Hill said after talks in Pyongyang.
Mr Hill paid a surprise visit to North Korea for talks
Mr Hill said a fresh round of six-party disarmament talks will be held in July.
In its first public response to talks earlier this week, North Korea said it would act as soon as it received funds frozen in a row over money laundering.
Russia, involved in the complex bank transfer, said on Saturday it had taken delivery of the $24m (£12.1m) funds.
The money is now expected to be claimed by North Korea, removing a key obstacle to the stalled deal agreed in February in Beijing.
The money was frozen for nearly two years in a Macau bank after the US said it was gained through drug smuggling and counterfeiting, making other banks unwilling to touch it.
North Korea said the talks with Mr Hill had been "comprehensive and productive", the official Korean Central News Agency reported.
N KOREA NUCLEAR DEAL
N Korea to 'shut down and seal' Yongbyon reactor, then disable all nuclear facilities
In return, will be given 1m tonnes of heavy fuel oil
N Korea to invite IAEA back to monitor deal
Under earlier 2005 deal, N Korea agreed to end nuclear programme and return to non-proliferation treaty
N Korea's demand for light water reactor to be discussed at "appropriate time"
The agency said the two sides agreed to resume six-party talks involving North Korea, South Korea, the US, Russia, Japan and China, in July.
Mr Hill said the shutdown would take place after North Korea reached an agreement with the UN's nuclear watchdog, the International Atomic Energy Agency (IAEA), on monitoring the operation.
Inspectors from the IAEA plan to visit North Korea on Tuesday for the first time since they were forced out of the country in 2002.
But Mr Hill added that closing the nuclear reactor was just the beginning of the process.
"Shutting down the reactor does not solve all our problems," he said.
Under the February deal, Pyongyang agreed to shut the reactor in return for the release of its frozen funds and additional aid and diplomatic benefits.
North Korea was promised one million metric tons of heavy fuel oil, to be supplied by the five other countries involved in the nuclear disarmament negotiations.