The Israeli military also confirmed it struck roads around Iran’s Fordo enrichment facility to obstruct access to the site. The underground site was one of those hit in Sunday’s attack by the United States on three nuclear facilities. The Israeli military did not elaborate.

In Tehran attacks, Israel’s Defence Ministry said it hit targets that included the notorious Evin Prison in the Iranian capital and the security headquarters of the paramilitary Revolutionary Guards.

“The Iranian dictator will be punished with full force for attacking the Israeli home front,” the ministry said.

Nuclear fears mount after US strikes

In Vienna, the head of the United Nations nuclear watchdog said he expected there to be heavy damage at the Fordo facility already following Sunday’s US airstrike there with sophisticated bunker-buster bombs.

“Given the explosive payload utilised … very significant damage … is expected to have occurred,” said Rafael Grossi, the head of the International Atomic Energy Agency.

With the strikes on Sunday on Iranian nuclear sites, the US inserted itself into Israel’s war, prompting fears of a wider regional conflict. Iran said the US had crossed “a very big red line” with its risky gambit to strike the three sites with missiles and 30,000-pound bunker-buster bombs.

Several Iranian officials, including Atomic Energy Organisation of Iran spokesman Behrouz Kamalvandi, have claimed Iran removed nuclear material from targeted sites ahead of time.

Grossi told the IAEA board of governors on Monday that Iranian Foreign Minister Abbas Araghchi had informed him on June 13 that Iran would “adopt special measures to protect nuclear equipment and materials”.

“I indicated that any transfer of nuclear material from a safeguarded facility to another location in Iran must be declared,” Grossi said, without saying whether Iran had responded.

Israel and Iran press their attacks

Iran described its Monday attack on Israel as a new wave of its Operation “True Promise 3”, saying it was targeting the Israeli cities of Haifa and Tel Aviv, according to Iranian state television.

Explosions were also heard in Jerusalem. There were no immediate reports of damage.

In Iran, witnesses reported Israeli airstrikes hit areas around Iran’s capital, Tehran, about midday. Iranian state television confirmed one Israeli strike hit the gate of Evin Prison.

The report shared what appeared to be black and white surveillance footage of the strike. The prison is known for holding dual nationals and Westerners often used by Iran as bargaining chips in negotiations with the West.

Evin also has specialised units for political prisoners and those with Western ties, run by the paramilitary Revolutionary Guard, which answers only to Supreme Leader Ayatollah Ali Khamenei. The facility is the target of both US and European Union sanctions.

Earlier on Monday, Iranian General Abdolrahim Mousavi, the chief of joint staff of armed forces, warned Washington its strikes had given Iranian forces a “free hand ” to “act against US interests and its army”.

Tens of thousands of American troops are based in the Middle East, many in locations within range of short-range Iranian missiles.

The US described its Sunday attack on the Fordo and Natanz enrichment facilities, as well as the Isfahan nuclear site, as a one-off to take out Iran’s nuclear program, but President Donald Trump has warned of additional strikes if Tehran retaliates.

Mousavi described the American attacks as violating Iran’s sovereignty and being tantamount to invading the country, the state-run IRNA news agency reported.

In the wake of the American attacks, calls came from across the globe for de-escalation and the return to diplomacy to try and resolve the conflict.

On Monday, the European Union’s top diplomat said the bloc remained “very much focused on the diplomatic solution”.

“The concerns of retaliation and this war escalating are huge,” Kaja Kallas said at the start of a foreign ministers’ meeting in Brussels where Iran has jumped to the top of the agenda.

After Sunday’s attacks, Iranian officials repeated their longtime threats of possibly closing the key shipping lane.

Iran, which insists its nuclear program is for civilian purposes only, previously agreed to limit its uranium enrichment and allow international inspectors access to its nuclear sites under a 2015 deal with the US, France, China, Russia, Britain and Germany in exchange for sanctions relief.

But after Trump pulled the US unilaterally out of the deal during his first term, Iran began enriching uranium up to 60 per cent — a short, technical step away from weapons-grade levels of 90 per cent — and restricting access to its nuclear facilities.

As he arrived in Brussels on Monday for a meeting with his EU counterparts, German Foreign Minister Johann Wadephul renewed calls for Iran to agree again to direct talks with the US but said Europe still had a role to play.

“We already made it very clear to the Iranian side that a real precondition for a settlement to the conflict is that Iran be ready to negotiate directly with the US,” he said, while adding that the European group known as the E3 “will contribute what we can”.

Iranian Foreign Minister Abbas Araghchi was meeting on Monday in Moscow with Russian President Vladimir Putin, one of Iran’s key allies.