Israel said early on Friday it had struck Iranian nuclear targets to block Tehran from developing atomic weapons, and Iranian media and witnesses reported explosions including at the country’s main uranium enrichment facility.

Calling the offensive “Rising Lion,” Israel said it was also targeting Iranian commanders and missile factories, and declared a state of emergency in anticipation of retaliatory missile and drone strikes by Tehran.

“We are at a decisive moment in Israel’s history,” Israeli Prime Minister Benjamin Netanyahu said in a recorded video message.

Israel targeted Iranian scientists working on a nuclear bomb, its ballistic missile programme and its Nantanz uranium enrichment facility, in an operation that would continue for days, he said.

A witness in Nantanz city said multiple explosions were heard near the facility, and a senior Iranian official told Reuters that the country’s leadership was holding a top security meeting.

Iran’s state TV said several explosions were heard in Tehran and the country’s air defence system was on full alert.

An Israeli military official said Israel was striking “dozens” of nuclear and military targets. The official said Iran had enough material to make 15 nuclear bombs within days.

“Following the preemptive strike by the State of Israel against Iran, a missile and UAV (drone) attack against the State of Israel and its civilian population is expected in the immediate timeframe,” Defence Minister Israel Katz said in a statement.

US Secretary of State Marco Rubio said Israel acted unilaterally because it believes the operation was necessary for self-defense.

“Tonight, Israel took unilateral action against Iran. We are not involved in strikes against Iran and our top priority is protecting American forces in the region,” Rubio said in a statement.

“Let me be clear: Iran should not target US interests or personnel,” he added.

CNN reported that US President Donald Trump was convening a cabinet meeting.

Crude oil prices jumped more than $3 a barrel on the news.

US and Iranian officials were scheduled to hold a sixth round of talks on Tehran’s escalating uranium enrichment programme in Oman on Sunday, according to officials from both countries and their Omani mediators. But the talks have appeared to be deadlocked.

Trump said on Thursday an Israeli strike on Iran “could very well happen” but reiterated his hopes for a peaceful resolution.

US intelligence had indicated that Israel was making preparations for a strike against Iran’s nuclear facilities, and US officials said on condition of anonymity that Israel could attack in the coming days.

The US military is planning for the full range of contingencies in the Middle East, including the possibility that it might have to help evacuate American civilians, a US official told Reuters, speaking on condition of anonymity.