Who is Sheikh Naim Qassem, Hezbollah's deputy leader who spoke on Monday?

Hezbollah's deputy secretary general Sheikh Naim Qassem said the group would appoint a new leader at the earliest opportunity to replace Sayyed Hassan Nasrallah and vowed that the Iran-backed movement would continue fighting Israel.

Qassem's 19-minute, televised address marked the first by a top Hezbollah leader since Nasrallah was killed on Friday in an Israeli airstrike, in a huge blow to the group as it reels from an escalating Israeli campaign of attacks.

Who is Qassem?

Here are some facts about Qassem.

- Qassem is a veteran figure in the group, having served as deputy secretary general since 1991.

- He was appointed deputy secretary general under Hezbollah's late secretary general, Abbas al-Musawi, who was killed by an Israeli helicopter attack in 1992, and remained in the role when Nasrallah became leader.

- His political activism began in the Lebanese Shi'ite Amal Movement, founded in 1974. He left Amal in 1979, in the wake of Iran's Islamic Revolution, which shaped the political thinking of many young Lebanese Shi'ite activists. He took part in meetings that led to the formation of Hezbollah, which was established by Iran's Revolutionary Guards in 1982.

- He has long been one of the leading spokesmen for Hezbollah, conducting many interviews with foreign media. As cross-border hostilities raged with Israel during the Gaza war, he told Al Jazeera in June that Hezbollah's decision was not to widen the war but that it would fight one if it was imposed on it.    

- He has been the general coordinator of Hezbollah's parliamentary election campaigns since the group first contested them in 1992.

- He was born in 1953 in Beirut's Basta Tahta district and his family originally hail from Kfar Fila, in Lebanon's predominantly Shi'ite south. He is married with six children.