US fears widening conflict about to explode in Middle East after Haniyeh killing

US Secretary of State Antony Blinken told foreign ministers from G7 countries on Sunday that Iran and Hezbollah could attack Israel as early as Monday, according to reports.

Fears are growing about the potential break out of a major regional war following the assassination of senior Iranian, Hezbollah and Hamas figures - including Ismail Haniyeh in Iran - with Tehran threatening revenge.

Blinken assembled his G7 counterparts in a conference call to urge Iran and its allies to de-escalate tensions but believes Iran and Hezbollah will both retaliate for the killings, US news outlet Axios reported.

There are fears the response could exceed Iran’s retaliatory attack against Israel last April following the assassination of top Iranian Revolutionary Guard Corps commander in Damascus.

While Israel, the US, and other allies worked to intercept Iranian drones and missiles during the last retaliation, the exact timing of the next attack has yet to be confirmed - not its scale - but the US believes it could start as early as the next 24 to 48 hours.

G7 ministers released a statement on Monday, urging restraint and de-escalation in the Middle East, stating that recent events "threatened to ignite a broader conflict in the region".

"We urge all involved parties to refrain from perpetuating the current destructive cycle of retaliatory violence, to lower tensions, and engage constructively towards de-escalation," the Group of Seven added.

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

France's Emmanuel Macron and Jordan's King Abdullah II on Sunday said a widening of the war in Gaza must be avoided "at all costs" during a telephone call on Sunday, according to the French presidency.

Meanwhile, Jordan's Foreign Minister Ayman Safadi concluded a rare visit to Iran on Sunday with a plea for "peace, security, and stability", as nearly 40,000 people are killed in Gaza.

"Jordan has always been proactive in defending the Palestinian cause and the rights of the Palestinian people," he said in a press conference alongside his Iranian counterpart.

"It has condemned the Israeli occupation of the Palestinian territories and rejected all of Israel's escalating measures that prevent achieving security, stability, and a just peace."

Additionally, Egypt has addressed concerns that a major assault on Israel by Iran and its proxies could be the next step toward a wider conflict in the region after Israel's killing spree.

Egypt Foreign Minister Badr Abdelatty stressed in a phone call with Iran's Acting Foreign Minister Ali Bagheri Kani that recent developments in the region were "unprecedented, very dangerous" and threatened stability.

Last week, Australia and South Africa warned against the region being plunged into further turmoil. 

Pope Francis has called for minimising violence in the region, hoping that the "violent, bloody" conflict will not expand further.

"Attacks, even targeted ones, and killings can never be a solution. They do not help to follow the path of justice, the path of peace, but generate even more hatred and revenge," the head of state of the Vatican said.

However, Iran’s foreign ministry spokesperson said on Monday that it is not seeking to escalate regional tensions but still believes Israel needs to be punished to prevent further instability.

According to Israeli media, an underground bunker in Jerusalem, prepared by Israel's Shin Bet security service, is said to be fully operational and can accommodate senior leaders - including Prime Minister Benjamin Netanyahu - for an extended period during wartime.

Concerns that the nearly 10-month war on Gaza could become a wider regional conflict have increased after the killing of Hamas leader Ismail Haniyeh in Iran and senior Hezbollah commander Fuad Shukr in Beirut last week.

In Gaza, over 39,000 people have been killed because of indiscriminate Israeli bombardment and ground attacks on the territory.