"Following the joint US-Israeli attack on Arag square in southern Tehran on Sunday evening, parts of the Golestan Palace... were damaged," the ISNA news agency reported, adding that windows, doors, and mirrors were hit by reverberations from blasts.

Iran's Mehr news agency carried a similar report.

The former royal palace "was reportedly damaged by debris and the shock wave following an air strike to the Arag Square, located in the buffer zone of the site in the Iranian capital", UNESCO said in a statement late on Monday.

The UN's cultural agency said it had "communicated to all parties concerned the geographical coordinates of sites on the World Heritage List as well as those of national significance, to avoid any potential damage".

It pointed to the protections for cultural property enshrined in international conventions.