Iran has vowed to avenge the death of one of its top generals after he was killed in a US airstrike in Iraq early on Friday morning.
Qassem Soleimani’s killing marks a significant escalation in the proxy conflict between Iran and the United States and risks igniting a conflict that could draw in other countries in the region, including Israel.
The Pentagon said the strike near Baghdad’s airport was ordered by President Donald Trump and was “aimed at deterring future Iranian attack plans”.
Mr Trump has not commented, although he has since tweeted a single photograph of a US flag.
Israel's Defence Minister Naftali Bennett convened top military officials for a security meeting on Friday morning and the IDF has been placed on high alert, Haaretz reported.
Meanwhile Prime Minister Benjamin Netanyahu cut short his trip to Athens, where he was signing a gas pipeline deal
In a statement issued on Friday afternoon, Mr Netanyahu praised Mr Trump for acting “swiftly, forcefully and decisively”.
“Just as Israel has the right of self-defence, the United States has exactly the same right,” he added.
Britain's Foreign Secretary Dominic Raab said the UK had “always recognised the aggressive threat posed by the Iranian Quds force”.
“Following his death, we urge all parties to de-escalate. Further conflict is in none of our interests,” he said.
Alistair Burt, the former British Foreign Office Minister for the Middle East, said the strike took the confrontation between the US and Iran “to a completely different level.”
“It is the killing of a very senior political as well as military commander,” he told BBC Radio 4.
“Any action where you cannot foresee the immediate consequences and take steps to prevent the most difficult consequences puts the region on edge and makes life more difficult for everyone.
“Everyone has to have cool heads this morning. This is a very grave escalation for the region.”