Satellite images indicate that North Korea has restarted its nuclear reactor at Yongbyon and is once again producing plutonium for its atomic weapons programme, a move that analysts suggest is a “political manoeuvre” designed to put more pressure on South Korea for the recent outbreak of détente to succeed.

Images obtained in late February show activity at the Yongbyon Nuclear Scientific Research Centre, including at the plant’s 5-megawatt reactor, and the deployment of what appears to be more military units at the site.

“A steam vapour plume was observed at the 5 MWe reactor on imagery from both February 17 and 25,” analysts reported on the 38 North web site, which is run by the US-Korea Institute at Johns Hopkins University.

Similar plumes have in the past “generally been a useful indicator of reactor operations”, the report adds, although they have usually been accompanied by the discharge of coolant water into a nearby river, marked by the melting of ice and snow.

While that is absent at present, they said, it is likely that the outfall pipe has been extended further into the river.