US President Joe Biden met his senior national security team on Monday as concerns grew of a possible Iranian retaliatory attack on Israel.

Mr Biden said he had been briefed on preparations to support Israel should it be attacked, while Secretary of State Antony Blinken said officials were working "around the clock" to prevent an escalation.

Tensions have risen over the last week following the assassination of Hamas' political leader Ismail Haniyeh, for which Iran has blamed Israel and vowed “severe” retaliation. Israel has not claimed responsibility for the assassination.

Numerous countries, including the US and UK, have also told their citizens to leave Lebanon, where it is feared Hezbollah, an Iran-backed militia and political movement, could play a role in any response.

Mr Blinken told his G7 counterparts in a call on Sunday that Iran and Hezbollah could launch an attack on Israel within 24 to 48 hours, according to comments cited by US news site Axios.

On Monday evening, Mr Biden said he and Vice President Kamala Harris met senior security officials to discuss the situation.

"We received updates on threats posed by Iran and its proxies, diplomatic efforts to de-escalate regional tensions, and preparations to support Israel should it be attacked again," he said in a post on X, formerly Twitter.

He added that steps being taken to defend US forces and respond to any attack against its personnel "in a manner and place of our choosing" were discussed after several US personnel were injured at a military base in Iraq on Monday.

Speaking to reporters earlier in the day, Mr Blinken said officials were "engaged in intense diplomacy pretty much around the clock with a very simple message: All parties must refrain from escalation".

"Escalation is not in anyone's interests. It will only lead to more conflict, more violence, more insecurity," he said.

He added that a ceasefire would "unlock possibilities for more enduring calm not only in Gaza itself but in other areas where the conflict can spread".

"It is urgent that all parties make the right choices in the hours and days ahead," he said.

His words came after Mr Biden spoke to King Abdullah II of Jordan earlier in the day. They discussed "their efforts to de-escalate regional tensions, including through an immediate ceasefire and hostage release deal," a statement from the White House said.

A joint statement from the G7 also expressed "deep concern at the heightened level of tension in the Middle East which threatens to ignite a broader conflict in the region".

"No country or nation stands to gain from a further escalation in the Middle East," it said.

Talks that had brought renewed hope of a ceasefire deal to end the conflict in Gaza have faltered following Haniyeh's death - which capped a week of soaring tensions in the Middle East.

Things first escalated with the killing of 12 children and teenagers in a strike on the Israeli-occupied Golan Heights some days ago. Israel accused Hezbollah and vowed “severe” retaliation, though Hezbollah denied it was involved.

Days later, Fuad Shukr, a senior Hezbollah military commander, was killed in an Israeli airstrike on a suburb of the Lebanese capital, Beirut. Four others, including two children, were also killed.

And just hours later, Haniyeh was assassinated in Iran.

Iran's Revolutionary Guard Corps (IRGC) said Haniyeh was killed in a "strong blast" caused by a "short-range projectile" fired from outside a house where he was staying while visiting the capital, Tehran.

Israel has not commented on the death but Israeli Prime Minister Benjamin Netanyahu said afterwards that Israel delivered “crushing blows” to Iran’s proxy groups in recent days.

Following the killings in Lebanon and Iran, the IRGC said Israel would receive a "severe punishment at the appropriate time, place and manner", while Hezbollah leader Hassan Nasrallah said the conflict had entered a "new phase".

It marks the closest the conflict has come to escalation since April when Iran fired some 300 drones and missiles at Israel in response to an Israeli strike on an Iranian consulate in Syria that killed a number of senior military commanders.

The conflict in Gaza began following the 7 October attack on Israel by Hamas and other militant groups, which saw around 1,200 people killed and another 251 taken back to Gaza as hostages.

Since the launch of Israel's retaliatory ground invasion in Gaza, more than 38,400 Palestinians have been killed, according to the Hamas-run health ministry.

Hundreds of people have also been killed and tens of thousands displaced from their homes on both sides of the Israel-Lebanon border by near-daily attacks between Israeli forces and Hezbollah.

On Monday, Jordan asked all airlines planning to land at its airports to carry an additional 45 minutes' worth of fuel, a move believed to be a precaution in case Jordan has to close its airspace in the event of a regional conflict.

German flag carrier Lufthansa has suspended all flights to Tel Aviv, Tehran, and Beirut until and including 12 August.

US airline Delta has also paused flights to Tel Aviv until at least 31 August "due to ongoing conflict in the region".

The Foreign Office currently advises against all travel to Lebanon and has urged British citizens in the country to leave.

It also advises against all travel to the northern area of Israel that shares a border with Lebanon.

On Monday, several US personnel were injured in a suspected rocket attack on an American military base in western Iraq.

US officials have not yet said who they believe was behind the attack.