Seoul, May 5 (IANS): North Korea's Punggye-ri nuclear test site has shown "a very low level of activity" despite warnings that Pyongyang could carry out a new atomic test ahead of an important congress which begins on Friday.

Satellite images taken early this week and analysed on Thursday by monitoring group, 38 North, showed no vehicles or workers at many areas of the site, indicating that no preparations for an underground nuclear test are underway, EFE news reported.

South Korea said recently that North Korea could carry out its fifth nuclear test in the coming days to strengthen the position of leader Kim Jong-un ahead of the important Workers' Party Congress - the first one in 36 years - which starts on Friday.

Nonetheless, 38 North said it was clear "Pyongyang has made all necessary preparations to conduct a nuclear test".

Kim Jong-un's regime conducted its fourth underground nuclear test on January 6 during which it claimed that it successfully detonated a hydrogen bomb, although international experts doubt the claim.

On February 7, Pyongyang also put in orbit its second space satellite, an action widely seen as a disguised missile test.

The two actions led the UN Security Council to impose its toughest sanctions so far on the country, which some believe could choke off the economy of the isolated regime.