North Korea appears to halt construction at rocket site

WASHINGTON (CNN) -- North Korea appears to have stopped work on a long-range missile launch site, according to newly released satellite imagery.

The analysis by 38 North, a blog run by the School of Advanced International Studies at Johns Hopkins University, shows construction at the Tonghae launch site appears to have stopped eight months ago.

But as with everything when it comes to the opaque workings of North Korea, the search for a definitive reason behind the stoppage remain elusive.

"It's almost certain they are not going to stop developing long-range missiles. I don't think that's what is going on here," says Joel Wit, a former State Department official who manages the blog and studied the images. "We have to be very careful about trying to say what is going on, because the fact is we really don't know."

In addition to still incomplete roads around the site that would carry materials to the launch pad, the images also show grass and other vegetation growing over the foundation of the new assembly building at the Tonghae site. The images were taken on May 26.

Construction began on Tonghae in 2011 and the site is separate from the Sohae facility from where a long-range rocket successfully launched a satellite into orbit last December.

Explanations for the stoppage range from the diversion of workers to other parts of the country to help with reconstruction following the heavy rains and typhoons in 2012, to a decision by the government of Kim Jong-un that it does not need a second facility to test long-range rockets.

"We're sort of at the thin edge here where we see something's happening, but we need more time to figure it out," Wit said.

Satellite imagery released earlier this month showed North Korea moving ahead with efforts to improve and possibly modernize its missile program through a series of engine tests. Those tests appeared to be done at the Sohae launch facility.

Analysts who follow North Korea say the Tonghae site always appeared to be designed to handle larger rockets, perhaps even larger than the Unha rockets the North launched in their two previous tests last December and April.

Earlier imagery of the site based on the launch pad, fuel tanks, and size of the missile assembly facility suggested a support site for rockets perhaps two to three times as large as those already tested. The Sohae site is also capable of launching rockets larger than the Unha.

But the question of whether work will ever continue at the newer site will likely have to wait for another day.

"If we go through the summer and nothing is happening, you probably could conclude that it does not look like they are going to restart, but it's a little premature for that," Wit said.