PYONGYANG - Recent satellite imagery suggests North Korea is unlikely to conduct a fresh nuclear test in coming months, according to a US think-tank.

The Stalinist state recently turned up the volume on its hostile rhetoric and boasted of its nuclear and missile capability, claiming it had successfully tested a submarine-launched ballistic missile last month.

But the US-Korea Institute at Johns Hopkins University said satellite pictures indicate no signs of preparations for its fourth nuclear test being made at this time.

"Recent commercial satellite imagery indicates that North Korea is conducting regular spring construction and maintenance activities at its Punggye-ri nuclear test site," the institute said in a report by analyst Jack Liu on its website 38 North.

"There are no indications of nuclear test preparations at this time. Given the time and effort such preparations require, North Korea is unlikely to conduct another nuclear test until at least fall 2015 at the earliest," it said. (AFP)