Israeli Prime Minister Benjamin Netanyahu said late Sunday that his country was "determined to stand against" Iran and its allied armed groups "on all fronts," as Tehran vowed to retaliate against the assassination of the Hamas leader on its territory.

As the Israeli war on Gaza nears its 11th month, Israel has been bracing for retaliation from the "axis of resistance" for the assassinations of two senior figures.

Palestinian armed group Hamas's political leader Ismail Haniyeh was assassinated by Israel in Tehran on Wednesday.

The killing came hours after an Israeli strike on Beirut left Hezbollah military chief Fuad Shukr dead.

Tehran said Monday that "no one has the right to doubt Iran's legal right to punish the Zionist regime" for Haniyeh's killing.

US Secretary of State Antony Blinken told his counterparts from the G7 nations in a conference call on Sunday that any attack, which he expected to be a joint undertaking between Hezbollah and Iran, could happen within 24 to 48 hours, as early as Monday, US news site Axios reported.

Blinken asked his counterparts to place diplomatic pressure on Tehran, Hezbollah and Israel to "maintain maximum restraint", it added.

Israel's occupation army spokesman said on Sunday night that "as of now there is no change" in its policy.

US State Department spokesman Matthew Miller said on Monday the Washington "made it clear to Iran that they must avoid escalation and that we will defend Israel in the event of an attack."

"We don't think this attack has to happen and we are trying to prevent it," he added.

'Path of dialogue'
 

According to Miller, the US believes that a ceasefire in Gaza and the release of captives is the way to calm tensions in the region.

Experts and diplomats fear that the expected attack on Israel could rapidly spiral into a regional war.

Turkey on Monday joined multiple Western and other nations calling on their citizens to leave Lebanon, home to Hezbollah.

Numerous airlines have suspended flights to the country or limited them to daylight hours.

Germany's Lufthansa, which has already suspended flights to the region including Tel Aviv, said its planes would avoid Iraqi and Iranian airspace until at least August 7.

The United Nations' rights chief Volker Turk called on "all parties, along with those states with influence, to act urgently to de-escalate what has become a very precarious situation".

Italian Foreign Minister Antonio Tajani, whose country currently holds the rotating G7 presidency, said in a statement: "We call on the parties involved to desist from any initiative that could hinder the path of dialogue and moderation."

On Sunday, Jordan's Foreign Minister Ayman Safadi made a rare trip to the Iranian capital during which he delivered a message from King Abdullah II to President Masoud Pezeshkian.

Jordanian "airspace will probably be a theatre for missiles and anti-missile" fire in any direct Iranian-Israeli clashes, but Amman would strongly object to violations of its sovereignty, said political analyst Oraib Rantawi.

"The Iranians must find other ways to spare Jordan this embarrassment," Rantawi, director of the Amman-based Al Quds Center for Political Studies, told AFP.

The Israel war on the Gaza Strip has already drawn in militants in Syria, Lebanon, Iraq and Yemen.

Israel's genocidal campaign has killed at least 39,623 people in Gaza, mostly women and children.

Cross-border clashes
 

Even as the region braced for further escalation, Hezbollah and Israel continued their near-daily exchanges of fire.

The Lebanese health ministry said four people were killed in two separate strikes on the border towns of Mais al-Jabal and Hula, while the resistance group said it had targeted military sites in northern Israel with "explosive-laden drones".

Tehran has said it expects Hezbollah to hit deeper inside Israel and no longer be confined to military targets.

The cross-border violence since October has killed at least 549 people in Lebanon, mostly fighters but also including at least 116 civilians, according to an AFP tally.

On the Israeli side 22 soldiers and 13 civilians have been killed, according to army figures.

Israel's ally the United States said it was moving additional warships and fighter jets to the region.

US President Joe Biden was scheduled to meet with his national security team later Monday "to discuss developments in the Middle East", the White House said.

Far from the Lebanese border, the Israeli occupation army said around 15 rockets had crossed from the southern Gaza Strip into Israel on Monday, with medics saying they were treating an injured man.

Months of talks, mediated by Qatar, Egypt and the United States, aimed at a Gaza ceasefire and a captive-release deal have repeatedly stalled.

Hamas officials, some analysts, protesters in Israel, and even US President Joe Biden have accused Netanyahu of prolonging the war to safeguard his hard-right ruling coalition.

The killing of Haniyeh, who was Hamas's lead negotiator in truce talks, "does not suggest Israel is sincerely interested in a ceasefire", said Middle East expert Andreas Krieg.

* This story was edited by Ahram Online