Here are the latest developments:

- Iran Guards, Tehran prison -

Israel carried out "strikes of unprecedented force against regime targets and agencies of government oppression in the heart of Tehran", Defence Minister Israel Katz said as an AFP journalist heard loud blasts in the north of the Iranian capital.

Katz said the targets included the notorious Evin prison in the city's north, known to hold political prisoners and dissidents as well as foreign detainees.

Iran's judiciary confirmed Evin was struck, reporting "damage" and stressing the situation was "under control".

Israel also carried out a strike on Fordo, according to the military and Iranian media, a day after US "bunker buster" bombs hit the underground nuclear site south of Tehran.

In Israel, air raid sirens sent people to bomb shelters on Monday, with the military reporting at least three missile barrages in less than two hours.

The state power company said that "damage near a strategic infrastructure facility" in Israel's south caused outages. In Tehran, authorities said electricity supply disrupted by an Israeli attack was restored.

Israeli strikes on Iran since June 13 have killed more than 400 people, Iran's health ministry said. Iran's attacks on Israel have killed 24 people, according to official figures.

- 'Extension of war' -

Iran's armed forces threatened on Monday to inflict "serious, unpredictable consequences" on the United States in retaliation for its strikes on the Isfahan, Natanz and Fordo nuclear sites.

"This hostile act... will widen the scope of legitimate targets of the armed forces of the Islamic Republic of Iran and pave the way for the extension of war in the region," said armed forces spokesman Ebrahim Zolfaghari.

Ali Akbar Velayati, an adviser to Iran's supreme leader Ayatollah Ali Khamenei, said bases used by US forces "in the region or elsewhere" could be attacked.

The US embassy in Bahrain -- home to a major US military base -- reduced on-site staffing citing "heightened regional tensions".

- 'Spillover' -

China on Monday warned against "the spillover of war", urging the international community to do more to prevent the fighting from impacting the world's economy, noting the global importance of the Gulf maritime trade routes off the Iranian coast.

Oil prices briefly fell into the red on Monday after surging, as traders weighed possible retaliation by Iran.

US Secretary of State Marco Rubio called on China to help deter Iran from closing the Strait of Hormuz, a chokepoint for one-fifth of the world's oil supply.

The European Union's foreign policy chief, Kaja Kallas, said closing the strait would be "extremely dangerous".

Russian President Vladimir Putin slammed attacks on Iran as "unprovoked" and "unjustified" in a Moscow meeting with Tehran's Foreign Minister Abbas Araghchi, without announcing any concrete support to his key ally in the Middle East.

- Nuclear stockpiles -

The UN's International Atomic Energy Agency demanded Monday the return of inspectors to Iran's nuclear sites in a bid to "account for" its highly enriched uranium stockpiles.

"Allow IAEA inspectors... to go back to Iran's nuclear sites and account for the stockpiles of uranium" including the "400 kilograms enriched to 60 percent", said agency chief Rafael Grossi.

At an emergency meeting of the organisation's headquarters in Vienna, he said Tehran had sent him a letter on June 13 announcing the implementation of "special measures to protect nuclear equipment and materials".

burs-ami/jsa