Blog 38 North from the U.S.-Korea Institute at Johns Hopkins University states that satellite imagery of the Punggye-ri Nuclear Test Facility from late January reveals that the site "appears to be at a continued state of readiness."
A South Korean government source was quoted by the Chosun Ilbo newspaper as saying that Pyongyang may be preparing for two simultaneous tests at the facility. The sentiments were expressed because of activity near the southern edge of the test facility.
"There is a chance that the southern tunnel is a decoy but we aren't ruling out that the regime will conduct nuclear tests simultaneously at both tunnels," the source was quoted as saying.
South Korean, Japanese and U.S. officials met in Tokyo last week to discuss regional security concerns regarding North Korea.
North Korea in December launched a long-range rocket in an attempt to orbit a satellite. Similar launches in 2006 and 2009 coincided with nuclear tests.