Saleh al-Arouri, a senior official in Hamas’s politburo, was killed along with six others in the attack on the outskirts of Beirut. Israel has not taken responsibility, but concern was rising on Wednesday that the conflicts that its war with Hamas have sparked across the region could expand further.

Amid Israel’s bombardment of Gaza, and the support being offered by allies led by the US, violence has been on the rise in the occupied West Bank, on the Lebanon border, in Iraq and Syria, and in the Red Sea. There is now worry that the Beirut strike threatens to provoke a full war between Hezbollah, which is based in Lebanon, and Israel.

A spokesperson for the United Nations Interim Force in Lebanon (UNIFIL) said any potential escalation could have devastating consequences for people on both sides of the Blue Line – the demarcation line dividing Lebanon from Israel and the Golan Heights.

“We continue to implore all parties to cease their fire, and any interlocutors with influence to urge restraint,” Kandice Ardiel added.

French President Emmanuel Macron, in a call with Israeli war cabinet member Benny Gantz, urged Israel to “avoid any escalatory attitude, particularly in Lebanon”.

Despite the pleas from the West, the hit has also set off a new round of tough rhetoric across the region.

Israeli officials have reportedly been ordered not to discuss the killing of al-Arouri. But an Israeli military spokesman said “we are on high readiness for any scenario”.

Al Jazeera’s Laura Khan, reporting from occupied East Jerusalem, said the assassination is a major topic of discussion among the Israeli public.

“Everyone is talking about it, and it has been splashed across the headlines of newspapers,” which are using words like “eliminated” to describe his killing, she said.

Iran’s Foreign Ministry spokesman Nasser Kanaani said Arouri’s killing would “ignite another surge in the veins of resistance and the motivation to fight against the Zionist occupiers”.

Hamas politburo member Husam Badran said in a eulogy for al-Arouri: “We say to the criminal occupation that the battle between us is open.”

Hamas leader Ismail Haniyeh said the Palestinian group was “more powerful and determined” following the attack. “They left behind them strong men who will carry the banner after them.”

Regional war

Meanwhile, Lebanon’s caretaker Prime Minister Najib Mikati on Tuesday warned that the Israeli strike was an attempt to pull his country into the war.

“The explosion is an Israeli crime that clearly aims to bring Lebanon into a new phase of confrontations after the ongoing daily attacks in the south,” Mikati said.

Israel and Hezbollah have been trading low-level blows across the Lebanon border since the war in Gaza exploded, but the strike on al-Arouri threatens to push the pair into an all-out war.

Acting Foreign Minister Abdallah Bou Habib told the BBC that his government was speaking to Hezbollah to try to “convince” the movement not to react to the assassination.

“We are very concerned, [the] Lebanese do not want to be drawn into it; even Hezbollah does not want to be drawn into a regional war,” he was quoted as saying.

Hezbollah called the strike “a serious attack on Lebanon, its people, its security, sovereignty and resistance”.

“We affirm that this crime will never pass without response and punishment,” it said.

Much will now depend on the reaction of Hezbollah chief Hassan Nasrallah, who was due to make a speech in Beirut on Wednesday afternoon.

Previously he has warned Israel against carrying out assassinations on Lebanese soil, vowing a “severe reaction”.

Meanwhile, there is also concern that the strike could disrupt stuttering talks on a ceasefire plan put forward by Egypt.

Hamas officials said that al-Arouri was “at the heart of the negotiations” conducted by Qatar and Egypt.

An Israeli delegation was in Cairo on Wednesday to discuss the proposal, AP reported, quoting an unnamed Egyptian official. The killing of al-Arouri is likely to hamper the negotiations for a couple of days, the official added.

A victory Israel cannot guarantee

Unrest has also been stirred on the streets of the occupied West Bank.

Hundreds of Palestinians protested on Tuesday to condemn al-Arouri’s killing. A general strike was announced for Wednesday, and many shops and businesses remained closed across the territory.

“We’ve heard a lot of calls for revenge. And we’ve seen calls for a general strike … where Palestinians have said all schools and public institutions will be closed to mourn al-Arouri’s death,” Al Jazeera’s Nida Ibrahim reported from the city of Arura.

Ibrahim said people believe that Israel assassinated al-Arouri “to show its people a victory which it cannot guarantee in the besieged Gaza Strip”.