Amid escalating tension, UK Prime Minister Keir Starmer dials Iran's Masoud Pezeshkian

UK Prime Minister Keir Starmer and Iran President Masoud Pezeshkian

British Prime Minister Keir Starmer dialed Iran's President Masoud Pezeshkian on Monday and urged  him to "refrain from attacking Israel", Downing Street said.

"The Prime Minister said that he was deeply concerned by the situation in the region and called on all parties to de-escalate and avoid further regional confrontation," a Downing Street spokeswoman said following a joint statement by the US and European countries telling Iran to "stand down".

Besides the UK, the United States and European allies have called on Iran to "stand down", as fears mounted of an imminent attack on Israel that could spark an all-out war in the Middle East.

Following Iran's threat, tensions are soaring in the region, with the United States rushing a missile submarine and an aircraft carrier group in a show of support for its key ally.

Iran and its Lebanese ally Hezbollah have vowed revenge for the killing of the political leader of the Palestinian group Hamas in Tehran, and of a Hezbollah commander in Beirut.

International efforts to stave off an Iranian attack have intensified, with US President Joe Biden and the leaders of France, Germany, Italy and Britain warning Tehran in a joint statement on Monday.

"We called on Iran to stand down its ongoing threats of a military attack against Israel and discussed the serious consequences for regional security should such an attack take place," they said after speaking on Monday.

The White House warned that a "significant set of attacks" by Iran and its proxies was possible as soon as this week, saying that Israel shared the same assessment.

Meanwhile, Iranian President Pezeshkian said his country has the "right to respond to aggressors."

Hamas political chief Ismail Haniyeh had been in Tehran for the new Iranian president's inauguration last month when Haniyeh was killed in an attack that Iran has blamed on Israel.

Israel assassinated Hezbollah commander Fuad Shukr in Beirut a day earlier, leaving the region on edge.

(With agency inputs)