India, Sept. 10 -- With the Iran-US war reigniting after a brief lull, the United Nations atomic watchdog reportedly said it observed construction activity at Iran's Pickaxe Mountain, a heavily-fortified site suspected of housing nuclear-related activities.

The International Atomic Energy Agency has yet not inspected the tunnel complex but remote imagery indicates new movement at the site just south of Tehran's main uranium-enrichment plant, IAEA Director General Rafael Mariano Grossi said Thursday, Bloomberg reported.

"There are some indications that there is movement around this construction site," Grossi was quoted as saying. "We don't have any concrete information as to activities that may be taking place there."

Pickaxe Mountain, ...