Who is Hassan Nasrallah, the Hezbollah leader who vowed retaliation against Israel

Hassan Nasrallah, the leader of Hezbollah, is a powerful figure in Lebanon, backed by Iran and despised by Israel. He is revered by his Shiite followers and commands a well-equipped militia that surpasses the national army in strength. Nasrallah rarely appears in public since the 2006 war with Israel and delivers most of his speeches from an undisclosed location.
In his latest televised address, the 64-year-old cleric spoke after hundreds of Hezbollah operatives' communication devices were targeted in an unprecedented attack blamed on Israel.
Known for his oratory skills, Nasrallah can effortlessly switch from humour to rage in his speeches. He is always seen wearing traditional robes and a black turban, signifying his lineage to the prophet Mohammed. Nasrallah is married with four living children, having lost his eldest son Hadi in a military operation against Israeli troops in 1997.
Elected as Hezbollah's secretary general in 1992 at the age of 32, Nasrallah has led the group to become the only militia that retained its weapons after Lebanon's civil war ended in 1990. He maintains that Israel remains a significant threat to Lebanon.
Since the recent attacks on Hezbollah members' communication devices, Nasrallah has been under immense pressure to respond.
Born in Beirut in 1960, Nasrallah studied politics and the Koran in Iraq before being expelled in 1978. He became involved in Lebanese politics and gained experience in the Shiite Amal militia during the civil war.
However, he left Amal to co-found Hezbollah when Israel invaded Lebanon in 1982. Nasrallah's popularity soared after Israel withdrew its troops from south Lebanon in 2000, ending a 22-year occupation.
Under Nasrallah's leadership, Hezbollah has grown from a guerrilla faction into Lebanon's most influential political force. The group is admired by many Shiites for its charitable work and social services. Nasrallah's personal popularity peaked across the Arab world after the 2006 conflict with Israel ended in a UN-brokered ceasefire.
However, his reputation suffered during the 2011 Arab Spring protests when he sent fighters to support Syrian President Bashar al-Assad's regime.