The activity comes at a time of heightened tensions as talks between Iranian and US officials continue over Iran's nuclear ...

Tehran may have used the delay in the US's potential strike to make the beneath-mountain facility nearly untouchable.

Satellite images show Iran is reinforcing tunnel entrances at Mount Kolang Gaz La, also known as Pickaxe Mountain, one of its nuclear facilities. The development comes amid rising tensions with the US ...

Since the US bombed Iran's key nuclear sites last year, analysts say work has increased at a secret underground facility that could be used to restart Tehran's nuclear program.