ERBIL, Kurdistan Region of Iraq - The head of the UN’s nuclear watchdog on Wednesday renewed calls for Iran to allow inspections of the nuclear sites attacked by the US and Israel during the so-called “12-Day War” in June.

Israel killed top brass Iranian military commanders and nuclear scientists with airstrikes in June, prompting retaliatory attacks by Tehran, with the two trading salvos of missiles and drone strikes for 12 days. The US also bombed the key Natanz and Fordo nuclear sites in the country at the end of the skirmish.

Since the war, the International Atomic Energy Agency (IAEA) has been prevented by Iranian authorities from accessing the Fordo and Natanz sites, though it has been granted access to others.

“We have performed a number of inspections, but we have not been able to go to the attack sites. I hope we will be able. Indeed, we have to go because this is part of Iran's commitments,” Rafael Grossi told reporters in Vienna following a regular board meeting.

“I hope we'll be able to move in a constructive manner,” he said.

Tehran’s nuclear program has been a source of concern to Western states, who fear the regional consequences and shift in the balance of power should they acquire nuclear weapons.

Iran has repeatedly rejected claims of having ambitions to add nuclear warheads to its arsenal, insisting that its nuclear program is wholly civilian in nature.

In 2015, the Joint Comprehensive Plan of Action (JCPOA), also known as the Iran nuclear deal, came as a means to alleviate the concerns while providing Iran with sanction relief. The US reinstated sanctions on Iran in 2018 after Washington withdrew from the deal.

Since then, Washington and Tehran have held several rounds of indirect talks aimed at reviving a non-proliferation deal. Talks were indefinitely halted after the attacks in June.

According to AFP, the UK, France, Germany, and the US have drafted a resolution to the IAEA, urging Iran to “fully cooperate” with the agency.

The draft, which is expected to be voted on during the IAEA’s board meeting this week, stresses that it is “imperative” for Iran to comply with its obligations under the nuclear deal, AFP reported.

It also called on Iran to provide "access that the agency requests."

Earlier this month, Iranian President Masoud Pezeshkian said his country is rebuilding its nuclear facilities “with greater strength,” following the damage caused by the US and Israel.

In September, the UN reimposed crippling sanctions on Tehran for allegedly failing to fulfill its nuclear commitments. In turn, Iran blocked the nuclear watchdog from maintaining oversight of its facilities, citing the termination of the nuclear deal’s commitments.

The IAEA on Wednesday told AP that it lost “continuity of knowledge” on Iran’s near weapons-grade uranium stockpile since June, stressing that the issue must be "urgently addressed.”