​Israeli prime minister Benjamin Netanyahu has threatened to carry out direct military strikes targeting President Bashar al-Assad’s regime unless all Iranian forces are withdrawn from Syria.

The aggressive ultimatum to Damascus is a significant escalation in the confrontation in Syria between Israel and Iran.

The Syrian leader was “no longer immune, his regime is no longer immune. If he fires at us, we will destroy his forces,” Mr Netanyahu declared during a visit to London, speaking at a question and answer session at the Policy Exchange think tank.

Israel has carried out a number of air strikes on Iranian bases in Syria and has repeatedly demanded that Iran, which it considers “an existential threat”, must remove its forces and weapons from Syria.

But this was the first time that it had been stated that the Assad regime would be punished for the presence of Iranian forces, which have been fighting Isis and Islamist rebels.

Mr Netanyahu said: “I think there is a new calculus that has to take place and Syria has to understand that Israel will not tolerate the Iranian military entrenchment in Syria against Israel.

“The consequences are not merely to the Iranian forces there but to the Assad regime as well, I think it’s something that he should consider very seriously.”

The Israeli prime minister blamed Assad personally for the presence of Tehran’s forces in Syria as he warned of possible Israeli intervention.

“Assad has to consider this: when they waged this horrific civil war, Israel did not intervene. Now the war is nearly over, he invites Iran in to entrench itself?”

The Syrian leader was accused of facilitating Tehran “to move its army a thousand miles so it can threaten Israel. They want to bring in precision guided rockets with half a ton warheads and submarines to the Mediterranean… Iran does not believe in a master race, it believes in a master faith,” and is bent on conquest, Mr Netanyahu charged.

Assad has to consider this: when they waged this horrific civil war, Israel did not intervene. Now the war is nearly over, he invites Iran in to entrench itself? Benjamin Netanyahu, Israeli prime minister

The prime minister is on a tour of Western Europe to try to drum up support for further action against Iran, after US President Donald Trump reneged on an agreement between international powers and Tehran over its nuclear programme.

The other signatories to the deal – Britain, France, Germany, Russia and China – as well as the United Nations have all stressed that it was working and the Iranian government was abiding by its commitment.

Emmanuel Macron, Angela Merkel and Theresa May have told Mr Netanyahu that they are determined not to abandon the agreement, the scrapping of which could lead to nuclear proliferation in the region and beyond, they warned.

The Israeli prime minister maintained that his “real focus for this visit was not about the [nuclear] deal”.

That, he boasted, had been effectively destroyed by him and Mr Trump.

Israel attack Iran targets in Syria: overnight airstrike in pictures Show all 10 1 /10 Israel attack Iran targets in Syria: overnight airstrike in pictures Israel attack Iran targets in Syria: overnight airstrike in pictures Missiles rise into the sky as Israeli missiles hit air defense position and other military bases, in Damascus Syrian Central Military Media, via AP Israel attack Iran targets in Syria: overnight airstrike in pictures Missile fire is seen from Damascus Reuters Israel attack Iran targets in Syria: overnight airstrike in pictures An Israeli flag is seen placed on Mount Bental in the Israeli-annexed Golan Heights. Israel's army said today it had carried out widespread raids against Iranian targets in Syria overnight after rocket fire towards its forces it blamed on Iran, marking a sharp escalation between the two enemies. Israel carried out the raids after it said around 20 rockets, either Fajr or Grad type, were fired from Syria at its forces in the occupied Golan Heights at around midnight. AFP/Getty Israel attack Iran targets in Syria: overnight airstrike in pictures The Israeli military on Thursday said it attacked "dozens" of Iranian targets in neighboring Syria in response to an Iranian rocket barrage on Israeli positions in the Golan Heights AP Israel attack Iran targets in Syria: overnight airstrike in pictures Israeli artillery deployed missiles toward Syrian military targets, on the Golan Heights EPA Israel attack Iran targets in Syria: overnight airstrike in pictures Missile fire is seen over Daraa Reuters Israel attack Iran targets in Syria: overnight airstrike in pictures Air defence systems intercepting Israeli missiles over Syrian airspace AFP/SANA Israel attack Iran targets in Syria: overnight airstrike in pictures Israeli soldiers walk among armored vehicles in the Israeli-occupied Golan Heights Reuters Israel attack Iran targets in Syria: overnight airstrike in pictures Syrian air defense missiles are seen in the sky over the capital Damascus EPA Israel attack Iran targets in Syria: overnight airstrike in pictures Air defence systems intercepting Israeli missiles over Syrian airspace. Israeli missile strikes fired at Syria hit military bases, as well as an arms depot and military radar. AFP/SANA

He warned European businesses of the punitive fines they would face under American sanctions if they continued trading with Iran.

Mr Netanyahu stated that his aim on the trip, instead, was to “expose” how “Iran is devouring one nation after another” and ask Western European governments to do more “about reversing Iran’s aggression in the region and getting them out of Syria”.

The French, German and British leaders have all raised their concerns with Mr Netanyahu about the recent brutal violence at the Gaza border in which dozens of Palestinians were shot dead by Israeli troops.

The UK foreign secretary, Boris Johnson, urged the Israeli government to open an independent inquiry into the deaths and injuries suffered during the protests.

Asked at the London meeting why non-lethal methods, such as water cannons and rubber bullets, were not used, or even a policy of shooting at legs, rather than shoot to kill, not pursued, Mr Netanyahu insisted: “We have tried all these methods, they don’t work. These were not non-violent protests, quite the contrary.

“We are doing everything we can to both minimise casualties and, at the same time, protect Israeli lives.”