Pyangyong: New satellite images have shown "suspicious activity" at a North Korean nuclear facility at Yongbyon, 38 North, a Washington-based monitoring group announced on Tuesday.
Plumes of exhaust steam, a byproduct of heating the main plant at the Yongbyon Radiochemical Laboratory complex, have been seen in commercial satellite images taken on March 12 and over the preceding five weeks, CNN reported citing the monitoring group.
This activity was unusual, the report by the Washington-based project, said, adding that "exhaust plumes have rarely been seen there and none have been observed on any examined imagery this past winter".
"The plumes suggest that the operators of the reprocessing facility are heating their buildings, perhaps indicating that some significant activity is being undertaken, or will be in the near future."
The plumes of steam do not necessarily indicate that the process for refining plutonium for nuclear weapons is underway or will be soon," the report said.
It does, however, note that US Director of National Intelligence James Clapper recently testified that Pyongyang had "announced its intention to 'refurbish and restart' its nuclear facilities," including the uranium enrichment facility at Yongbyon and that it could be able to recover plutonium from the reactor's spent fuel "within a matter of weeks to months".
Separate images appear to showed further work on the site's Experimental Light Water Reactor (ELWR), a key facility for the enrichment of nuclear fuel, was ongoing, with a new transformer yard and road built, and the installation of electrical cables completed.
The report stated that "slow, steady progress" was being made on this component of Pyongyang's nuclear project.
Construction of new buildings near the Uranium Enrichment Complex was also ongoing, with some buildings nearing completion and new projects started. While there was speculation as to the purpose of these new buildings, the report said evidence was insufficient to reach any firm conclusions.
South Korean officials said they were aware of the report. "We are looking into... and closely monitoring the situation," South Korean Defence Ministry spokesman Moon Sang-gyun said during a regular press conference on Tuesday.