Lebanon's Hezbollah elected its deputy secretary general Naim Qassem to succeed slain head Hassan Nasrallah on Tuesday.
Qassem reportedly fled Beirut on October 5 for Syrian capital Damascus and then flew to Tehran for safety. He was also accompanied by Iranian Foreign Minister Abbas Araqchi. His evacuation was reportedly ordered by top Iranian officials as fears over his assassination grew.
Iranian sources said Qassem's October 15 address was delivered from Tehran. In his speech, Qassem said the group cannot be defeated by intense Israeli bombardment of its strongholds or the killing of its senior leadership.
Hezbollah's secretary-general Hassan Nasrallah was assassinated in an Israeli airstrike on September 27 in southern Beirut after leading the group for 32 years.
Hashem Safieddine, thought to be the most likely successor, was killed in Israeli strikes a week later.
The new leader was elected by Hezbollah's Shura Council, which sits at the top of Hezbollah's hierarchy, with five subordinating councils.
He is one of the group's earliest members from its formative years and one of its chief ideologues, and was appointed as Hezbollah's deputy chief in 1991 by the armed group's then-secretary general Abbas al-Musawi.
Al-Musawi was assassinated by Israel in a helicopter attack in 1992.
Analysts have said Qassem does not possess the same leadership qualities or charisma of Hezbollah's former secretary-general Nasrallah, although will fill the role during current desperate times.