Keir Starmer has urged Iran not to respond after Israel launched a series of airstrikes targeting military sites in Iran overnight, saying the Middle East needs to “avoid further regional escalation”.

Speaking at a press conference in Samoa, the prime minister said: “I am clear that Israel has the right to defend itself against Iranian aggression. I’m equally clear that we need to avoid further regional escalation and urge all sides to show restraint. Iran should not respond.

“We will continue to work with allies to de-escalate the situation across the region.”

The government said it was monitoring the situation in the Middle East closely after the strikes early on Saturday. The attacks did not target nuclear or oil facilities, two Israeli officials confirmed to the Associated Press.

A No 10 spokesperson said on Saturday morning the government supported “Israel’s right to self-defence and to protect itself in line”, so long as it adheres to “international humanitarian law”. The statement read: “Further escalation is in no one’s interest.”

Israel said its aircraft “struck missile-manufacturing facilities used to produce the missiles that Iran fired at the state of Israel over the last year”.

Iran said the airstrikes targeted military bases in Ilam, Khuzestan and Tehran provinces, causing “limited damage”.

In Syria, the state news agency, Sana, citing an unnamed military official, reported that “barrages of missiles from the direction of the occupied Syrian Golan and Lebanese territories targeted some military sites in the southern and central regions” early on Saturday. It said that Syria’s air defences had shot some of the missiles down.

In a recorded video statement shared on social media early on Saturday morning, the Israeli military spokesperson R Adm Daniel Hagari said: “The regime in Iran and its proxies in the region have been relentlessly attacking Israel since October 7 … including direct attacks from Iranian soil.

“Like every other sovereign country in the world, the state of Israel has the right and the duty to respond.”

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Two US officials, speaking on the condition of anonymity, confirmed to the Associated Press that there was no US involvement in Israel’s operation against Iran.

Israel had vowed to hit Iran hard after an Iranian missile barrage on 1 October. The US said in a statement that Israel’s latest attack on Iran should now “complete” the exchange of fire between the two enemy states.

The US secretary of defence, Lloyd Austin, spoke to Israel’s minister of defence, Yoav Gallant, to discuss the Israeli attack on Iran, reaffirming the US commitment to Israel’s security and right to self-defence.

According to a statement from the US Department of Defense, Austin reiterated its “ironclad” stance to defend US personnel, Israel and its partners across the Middle East “in the face of threats from Iran and Iran-backed terrorist organisations” and the US’s “determination to prevent any actor from exploiting tensions or expanding the conflict in the region”.