There has been heavy exchanges of fire between Israeli troops and members of Hezbollah along Lebanon’s southern border since the start of the Israel-Hamas war but now, a significant escalation is expected to take place as a result of a drone attack that killed a senior Hamas official.

On Tuesday, Saleh al-Arouri, 57, was killed in an Israeli drone attack on southern Beirut, Lebanon.

Al-Arouri was the deputy chief of Hamas’s political bureau and one of the founders of the group’s armed wing, the Qassam Brigades.

He had been living in exile in Lebanon after spending 15 years in an Israeli jail.

Echoing fears of further regional violence, the Lebanese Prime Minister, Najib Mikati, described the assassination as a “new Israeli crime intended to spur a new phase of conflict, following daily attacks in the south [of Lebanon].”

Lebanon issued a statement later on Tuesday saying that it would submit a complaint to the UN security council over the “blatant strike” on its territory.

Hezbollah has sworn to avenge the attack.

In a statement, Hezbollah said that the assassination was a “serious assault on Lebanon”, calling it a “dangerous development in the course of war between enemy and axis of resistance … [that] will not go without a response or punishment. The resistance has its finger on the trigger.”

Meanwhile, Mark Regev, an adviser to the Israeli Prime Minister Benjamin Netanyahu, said in an interview that Israel “has not taken responsibility for this attack.”

“But whoever did it, it must be clear – this was not an attack on the Lebanese state,” he said.

He added, “Whoever did this did a surgical strike against the Hamas leadership.”

Nonetheless, Israeli military spokesperson, Daniel Hagari disclosedthat Israeli forces were in a state of “high readiness” and prepared for any scenario after the killing of Arouri.

Asked to confirm that Israel was behind the strike, Hagari told a media briefing, “we are focused on killing Hamas.”

French President, Emmanuel Macron called Israeli Minister Benny Gantz following the attack on Beirut that killed Hamas’s deputy leader.

The French President’s office called on Israel to “avoid any escalatory attitude, particularly in Lebanon.”

Macron told Gantz that France is passing “these messages to all players directly or indirectly involved in the area.”

The French president also reiterated calls for a “lasting ceasefire” and expressed again his “deepest concern” at the mounting civilian death toll in Gaza.

Arouri’s assassination is likely to complicate negotiations between Hamas and Israel over the hostages the militant group holds in Gaza, with Arouri described as playing a key role in negotiations for the captives’ release.

Hamas “Neither Defeated Nor Destroyed”

In their latest battlefield assessment, the Institute for the Study of War (ISW) and the Critical Threats Project (CTP) said that Hamas is “neither defeated nor destroyed” as a military force.

They added that the change in Israeli tactics will “allow Hamas to rebuild its military capabilities and infrastructure.”

“Hamas maintains a conventional military structure, meaning that it should be able to quickly replace commanders who have died in the war,” the war monitors said.

ISW and CTP said that Israel’s withdrawal of five brigades from northern Gaza indicates the start of what Israel has described as a new phase in its war on the Palestinian territory.

According to the US-based military think tanks, this new phase of fighting entails the end of major combat operations and a transition to “targeted raids” by the Israelis.

Commenting on the targeted killing of Hamas official Saleh al-Arouri in southern Beirut on Tuesday, the ISW and CTP said that Israeli officials are now preparing for “a very significant response”, an Israeli media report stated.