Satellite imagery has shown vehicle activity at a North Korean missile site on the outskirts of Pyongyang, which could signal the imminent launch of missiles or missile engine tests, CNN said Sunday, citing US defense officials familiar with the latest assessment.

Vehicles have been spotted at the missile research center in recent days, but they are not believed to be fueling missiles. The US officials were uncertain whether the North was preparing to launch short or medium-range missiles or engine tests.

“The activities are consistent with what we’ve seen prior to other missile tests,” one US official was quoted as saying. While there was no sign of an imminent launch, the North could do so as always, other US officials added.

Researchers at the Middlebury Institute, who have monitored the site since 2017, told CNN the recent activity was inconclusive, and Pyongyang, which is aware that Washington is watching over the site, could be misleading US intelligence.

“The unusual traffic is difficult to interpret. If it is a leadership visit to the factory, that could come either at the beginning or the end of the construction of an ICBM or space launcher,” said Jeffrey Lewis, director of the Institute’s East Asia Nonproliferation Project.

“The important thing is that there is an uptick in activity at the site, just as there has been at Sohae and other facilities.” The North has carried out rocket tests at Sohae Satellite Launching Station, also known as the Tongchang-ri site.

The recent activity came days after North Korean leader Kim Jong-un announced he would unveil a “new strategic weapon” in the face of what Pyongyang denounces as Washington’s “hostile policy” toward the regime. The North blames the US for the deadlock in their nuclear talks, demanding concessions to resume the talks.

US officials said they they have reached out to the isolated regime to rekindle negotiations since their last working-level talks fell apart in October. There the two countries failed to reconcile differences over denuclearization steps. The US wants disarmament first, but the North insists on sanctions relief.

“We’ve been letting them know, through various channels, that we would like to get those (negotiations) back on track and to implement Chairman Kim’s commitment” to a nuclear-free Korean Peninsula, US national security adviser Robert O’Brien said on Jan. 10.

US Defense Secretary Mark Esper said Friday that the North is trying to build ballistic missiles carrying warheads, but supported a diplomatic initiative and political agreement as the best way to resolve the crisis.

By Choi Si-young (siyoungchoi@heraldcorp.com)