However one or more tunnels at the Punggye-ri nuclear test site are complete and ready for another test should Pyongyang decide to carry one out, the US-Korea Institute at Johns Hopkins University said.
On its closely-watched 38 North website, the institute said commercial satellite pictures of the Punggye-ri test site revealed no signs of test preparations.
"As a result, a fourth nuclear test seems unlikely in the near-term, for at least the next two to three months," 38 North said.
The North has so far conducted three nuclear tests at the Punggye-ri site in its northeast, in 2006, 2009 and 2013.
More From This Section
Pyongyang in November threatened to carry out its fourth test in response to a UN resolution condemning its human rights record.
But last week it offered to "temporarily" suspend any future test if the United States cancels its annual joint military drills with South Korea this year.