The United States has said it is working “around the clock” to avert an all-out war in the Middle East, as Israel remained on high alert for potential Iranian retaliation for two high-profile killings, AFP reports.

US President Joe Biden, whose country has sent extra warships and fighter jets to the region in support of Israel, held crisis talks on Monday with his national security team.

Biden and his top diplomat Antony Blinken sought to calm tensions that have soared since a suspected Israeli attack killed Hamas political chief Ismail Haniyeh in Iran.

Biden called King Abdullah II of Jordan, which helped down Iranian drones and missiles in an attack on Israel in April, while Blinken called top officials in Qatar and Egypt, the key intermediaries seeking a ceasefire in the 10-month Israel-Hamas conflict in Gaza.

“We are engaged in intense diplomacy, pretty much around the clock, with a very simple message — all parties must refrain from escalation,” Blinken said after joining other top officials in a White House meeting.