Benjamin Netanyahu on Thursday vowed to “harm” anyone who attacks Israel amid fears that Iran is poised to launch an unprecedented direct missile attack on its old enemy.

Benjamin Netanyahu has ordered Israeli jets carry out drills to simulate a strike on Iran .

The Israeli prime minister said “whoever harms us, we will harm them” after US intelligence officials warned that Tehran is preparing a strike that could plunge the Middle East into a new war.

Israeli jets carried out drills simulating a strike on Iran, local media reported, while Western and Arab diplomats scrambled to persuade the Islamic republic against military action.

Elite Iranian forces based in Syria have moved into civilian hotels in anticipation of Israeli blowback, security sources told The Telegraph.

Rear Admiral Daniel Hagari, Israel’s chief military spokesman, said civilians were not being told to make any special preparations but added that the country was “highly prepared for a range of scenarios”.

On Thursday, Annalena Baerbock, Germany’s foreign minister, urged “maximum restraint” in a call with her Iranian counterpart.

Senior US Republicans demanded that Joe Biden order the military to join Israel in a “devastating” response to any Iranian attack.

Ayatollah Khamenei, Iran’s Supreme Leader, promised revenge for the killing of senior generals in an Israeli drone strike in Damascus in April. He said on state TV: “The evil regime must be punished, and it will be punished.”

Iranian state media said the nature of the response had been decided and “punishment” would be heavy.

On Thursday, Iranian diplomats said Tehran will soon respond to the Damascus attack, claiming this could have been avoided.

“Had the UN Security Council condemned the Zionist regime’s reprehensible act of aggression on our diplomatic premises in Damascus and subsequently brought to justice its perpetrators, the imperative for Iran to punish this rogue regime might have been obviated,” the Iranian mission to the United Nations said on social media.

The US has communicated to Iran that it was not involved in the Damascus strike, Karine Jean-Pierre, the White House press secretary, told reporters. “We have warned Iran not to use this attack as a pretext to escalate further in the region or to attack US facilities or personnel,” she said.

Tom Cotton, a Republican senator, warned that an Iranian attack on Israel was “imminent” and said: “President Biden needs to warn the Ayatollahs immediately that the United States will back Israel to the hilt and the joint American-Israeli retaliation for any attack will be swift and devastating.”

Antony Blinken, the US secretary of state, phoned his counterparts in China, Turkey, Saudi Arabia and Europe to ask them to use their influence to “urge Iran not to escalate”, the State Department said Thursday.

Mr Blinken also spoke with Yoav Gallant, the Israeli defence minister, “to reiterate our strong support for Israel against these threats”.

Open warfare between Israel and Iran would be an unprecedented escalation in the conflict between Israel and Hamas, the Iranian-backed terrorist group in Gaza behind the Oct 7 massacre.

Rishi Sunak, the Prime Minister, said on Thursday that the “threats from Iran are completely unacceptable” and stressed that “we have always said that we will support Israel’s ability to defend itself”.

David Cameron, the Foreign Secretary, wrote on X, formerly Twitter: “Today I made clear to Foreign Minister Amir-Abdollahian that Iran must not draw the Middle East into a wider conflict.

“I am deeply concerned about the potential for miscalculation leading to further violence. Iran should instead work to de-escalate and prevent further attacks.”

Marco Rubio, a senior Republican on the US senate intelligence committee, said the tensions marked “the most dangerous Middle East moment since 1973,” referring to the Yom Kippur war.

He added that Iran “wants to launch a large-scale attack from their own territory against Israel. Israel will respond instantly with an even more severe counter-attack inside of Iran”.

It was unclear whether he had personally seen US intelligence reflecting this or was commenting on media reports.

The Telegraph understands that several senior Iranian security and intelligence officials in Damascus moved to two civilian hotels for secret military meetings two days ago, converting them into operations rooms to discuss military plans.

A security source said both hotels were hosting members of the Iranian Revolutionary Guard who work in Syria, and Iran had transferred them there to ensure their safety after last week’s attack in Damascus.

Israel has not publicly claimed responsibility for that attack, although US and Israeli officials have acknowledged it was carried out by Israel.