Satellite images show Iran building at its underground Fordo nuclear site amid tensions with the U.S.

DUBAI, United Arab Emirates (AP) — Iran has begun construction at its underground nuclear facility at Fordo amid tensions with the U.S. over its atomic program, according to satellite images obtained Friday by The Associated Press.

Those images from Maxar Technologies show Iran has cleared and dug out a site potentially for a building at Fordo’s northwest corner. That’s where analysts previously identified a cluster of buildings as providing support and research and development there.

Iran has not publicly acknowledged the construction. Iran’s mission to the United Nations did not immediately respond to a request for comment, nor did the International Atomic Energy Agency.