Lebanon's Hezbollah movement has announced it has chosen deputy head Naim Qassem
in an Israeli strike in south Beirut last month.
"Hezbollah's Shura Council agreed to elect ... Sheikh Naim Qassem as secretary general of Hezbollah," the Iran-backed group said in a statement more than a month after Nasrallah's killing.
Qassem was elected by the five-member Shura Council, the group's main decision-making body, two days before Tuesday's announcement, a source close to Hezbollah said.
The source, who spoke on the condition of anonymity because he is not authorised to talk to the press, said a new Shura Council would be elected after the end of the war.
The source said the council may then opt to elect a new leader or keep Qassem in the top post.
Qassem had long operated in the shadows of
in the Middle East.
, was initially tipped to succeed Nasrallah. But he, too, was killed in an Israeli strike on Beirut's southern suburbs shortly after Nasrallah's assassination.
Who is Naim Qassem?
Qassem, 71, was one of Hezbollah's founders in 1982 and had been the party's deputy secretary general since 1991, the year before Nasrallah took the helm.
He was born in Beirut in 1953 to a family from the village of Kfar Fila on the border with Israel.
He was the most senior Hezbollah official to continue making public appearances after Nasrallah largely went into hiding following the group's 2006 war with Israel.
Since Nasrallah's death on 27 September, Qassem has made three televised addresses.
Naim Qassem was one of Hezbollah's founders in 1982 and has been the party's deputy secretary general since 1991. Source: EPA, AAP / Wael Hamzeh
Qassem said Hezbollah's military capabilities were intact and backed efforts by parliament speaker Nabih Berri to broker a ceasefire.
In his last speech on 15 October, Qassem said a ceasefire was the only way Israel could guarantee the return of its residents to the north.
The Israel-Hezbollah war erupted last month after nearly a year of cross-border fire.
On 23 September, Israel ramped up strikes on Hezbollah strongholds and sent in ground forces while killing one member of the group's top leadership after another.
Since then, the war has killed more than 1,700 people in Lebanon, according to an AFP tally of health ministry figures, though the actual number is likely to be higher due to gaps in the data.
The Israeli military says it has lost 37 soldiers in its Lebanon campaign since it launched ground operations on 30 September.