IAEA chief Rafael Grossi has said the situation in the Middle East was “very concerning”, urging “utmost restraint” after Israeli-US strikes on Iran and its retaliatory missile attacks, AFP reports.

The Vienna-based IAEA held an extraordinary session on Iran at the request of Russia, a key ally of Tehran, following the same request by Iran over the weekend.

“I reiterate my call on all parties to exercise maximum restraint to avoid further escalation,” Grossi said in his statement, released by the IAEA, as he opened the closed-door session.

“Iran and many other countries in the region that have been subjected to military attacks have operational nuclear power plants and nuclear research reactors, as well as associated fuel storage sites, increasing the threat to nuclear safety,” he added.

“Let me underline that the situation today is very concerning. We cannot rule out a possible radiological release with serious consequences, including the necessity to evacuate areas as large or larger than major cities,” Grossi warned.

The agency was trying to contact the Iranian nuclear regulatory authorities “with no response so far”, he said. He called for diplomatic negotiations to resume “as quickly as possible”.