Lebanese terrorist group Hezbollah has appointed Naim Qassem as the replacement for its slain chief Hassan Nasrallah, and Israel has already placed a target on his life.

“Temporary appointment. Not for long,” Israeli Defense Minister Yoav Gallant wrote on X Monday alongside a photo of Qassem. “The countdown has begun.”

Qassem, 71, assumed the role of acting leader following Nasrallah’s death in an Israeli airstrike in Beirut on Sept. 27. The new Hezbollah leadership was expected to be passed to Nasrallah’s cousin, Hashem Safieddine, but on Oct. 22, it was revealed that he too had died in an Israeli air strike nearly three weeks prior.

A founding member of Hezbollah, Qassem had served for more than 30 years as Nasrallah’s second-in-command and emerged as a prominent spokesperson for the group, especially as the clash with Israel along Lebanon’s border has escalated since last October.

He is also one of the few high-ranking Hezbollah leaders still alive after Israel’s targeted airstrikes decimated much of the group’s senior leadership in recent weeks.

In a stern warning, Israel said Qassem may soon meet the fate of his comrades.

“His tenure in this position may be the shortest in the history of this terrorist organization if he follows in the footsteps of his predecessors Hassan Nasrallah and Hashem Safieddine,” reads a post from the Israeli government’s Arabic-language X account. “There is no solution in Lebanon except to dismantle this organization as a military force.”

Qassem was born in 1953 in southern Lebanon. He was a Shiite cleric until the late 1970s when he joined the Amal movement during the Lebanese Civil War between Maronite Christians and Muslims.

In 1979, in the wake of Iran’s Islamic Revolution, Qassem broke away from Amal as it drifted in a more secular direction. In 1982, together with several like-minded former Amal members who shared his radical Islamist ideology, they founded Hezbollah.

In 1991, Qassem was appointed deputy leader under founding leader Abbas al-Musawi, who was killed in an Israeli attack the following year. Qassem continued in this role when Nasrallah became the leader and served as his deputy until Nasrallah’s death.

Since Nasrallah’s killing, Qassem has given several televised addresses, including one on Sept. 30, in which he told supporters that his group would “fill the leadership and positions on a permanent basis” and continue to fight against Israel in solidarity with the Palestinians.

“What we are doing is the bare minimum ... We know that the battle may be long,” he said in a 19-minute speech, speaking in front of wooden panels from an undisclosed location.

Tensions between Israel and Hezbollah have been ongoing for decades and have escalated in the past year since the Oct. 7, 2023, attack on Israel by Hamas—also an Iran-backed terrorist group—which killed 1,200 people, injured thousands, and kidnapped more than 250.

Israel’s retaliatory strikes in Gaza later that day were met with Hezbollah’s rockets, missiles, and drones in support of Hamas, prompting Israel to return fire.