UN nuclear watchdog 'increasingly concerned' about nuclear facility in Iran that it can't inspect

The International Atomic Energy Agency, the UN nuclear watchdog, said it is "increasingly concerned" about a nuclear facility in Iran that it has not been allowed to inspect. 

The day before Israel began attacking Iran's nuclear sites last June, Tehran informed the IAEA of plans to set up the uranium enrichment facility in the city of Isfahan, the BBC reported. The U.S. joined the strikes later that month. 

The IAEA said it does not know the exact location or whether it contains nuclear material. Iran has restricted inspectors' access to its nuclear sites since the beginning of the current conflict, and the IAEA has no means of verifying the country's uranium enrichment stockpile. 

The nuclear complex at Isfaharn suffered extensive damage from the U.S. and Israeli sites, but the condition of the underground facilities isn't known. 

"The Agency's lack of information about [Iran's] nuclear material and access to facilities to verify it is a matter of serious proliferation concern . . .and needs to be rectified with the utmost urgency," the IAEA said in the latest report.