North Korea plans to seal its main nuclear reactor and source of weapons-grade plutonium in the second half of July, Russia's Interfax news agency reported on Monday, citing an unidentified North Korean diplomatic source.
"To stop the reactor, it will take about a month according to our specialists," Interfax quoted the source as saying.
"So we are counting on sealing it (the reactor) in the second half of July, in accordance with the agreements reached at the six-party talks," the source said.
The report comes as North Korea said at the weekend it has invited UN nuclear inspectors into the country as part of a deal reached in February to shut down its Soviet-era Yongbyon reactor in exchange for aid.
The diplomatic source said the delegation from the International Atomic Energy Agency (IAEA) would be present at the first stage of stopping the reactor.
"We plan to invite the experts of the IAEA a second time, when the reactor is fully sealed in order to convince them of that," the source was quoted as saying.
US and South Korean officials were encouraged by the developments and saw a good chance for progress in the nuclear deal reached in February among the two Koreas, China, Japan, Russia and the United States.
Assistant Secretary of State Chris Hill said he expects the closing of the Yongbyon nuclear reactor, source of fuel for a suspected nuclear weapons program, can take place in a matter of weeks.
Speaking in Beijing where he was meeting Chinese diplomats, Hill said North Korea could now move forward more quickly to disable the reactor, making up for time lost while Pyongyang waited for $25 million frozen in a Macau bank account to be released.