( Reuters ) - 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," the source said, Interfax reported.
"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 U.N. 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.
South Korea has contacted at least two refiners to supply North Korea with 50,000 tons of oil pledged to Pyongyang if it started to shut the Yongbyon nuclear plant located about 100 km ( 60 miles) north of Pyongyang, industry sources said in Seoul said on Monday.
"The ministry has already notified a number of refiners so that the purchase could be made within this week," said a refinery source.
U.S. 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.
From a technical point of view, he said, disabling the reactor could be a matter of weeks, and he urged renewed momentum in the process.
"I think we do have to pay attention to timelines."
Pyongyang's move followed the release last week of the funds blocked in Macau for almost two years for suspected links to illicit activity by the North.
Pyongyang's insistence on the release had stalled international efforts to begin closing North Korea's nuclear arms program based on a February 13 agreement.
Pyongyang, which conducted its first nuclear weapons test in October, could receive massive energy aid and improved diplomatic standing if it scraps its atomic arms ambitions and defuses one of the region's most pressing security concerns.