Hezbollah is considered a terrorist organisation by Washington, which considers that the group was responsible for anti-Western attacks in Lebanon in the 1980s at the height of the country's 15-year civil war.

Nasrallah has denied links with anti-Western attacks, which were blamed by the West on Shiite regional powerhouse Iran, whose revolutionary guards helped to found Hezbollah in Lebanon.

On Thursday, the Hezbollah leader warned that a Lebanese government crackdown on his group was tantamount to a 'declaration of war,' as a long-running political crisis threatened to spiral out of control.

He also said his powerful militant group was ready to use its weapons to defend itself, as a confrontation between Lebanon's rival factions descended into street clashes.

'The (government) decisions are tantamount to a declaration of war and the start of a war... on behalf of the United States and Israel,' Nasrallah said at a rare press conference via video link. He rarely appears in public over fears for his security.

Nasrallah, who maintains close links with the Iranian leadership, insists that military action by Hezbollah is legitimate resistance against the Israeli occupation.

On July 12, 2006 Hezbollah guerrillas launched a cross-border attack and captured two Israeli soldiers in a bid to secure a prisoner swap.

But the incident sparked a 34-day war with Israel that left more than 1,200 dead in Lebanon, mostly civilians, and 161 Israelis dead, most of them soldiers.

The charismatic Nasrallah, 47, is a skilled orator with a sense of humour unusual among those in fundamentalist movements in the Middle East. He is also considered to be the military mastermind behind Hezbollah.

Born in Beirut's impoverished northern suburb of Burj Hammud on August 31, 1960, he was one of nine children of a poor grocer hailing from the tiny southern village of Bazuriyeh.

Intelligent and deeply religious, Nasrallah studied both politics and the Koran for three years at a Shiite seminary in Najaf, Iraq before being expelled in 1978 when then President Saddam Hussein, a Sunni, repressed Shiite activists.

He then became heavily involved in Lebanese politics and gained much of his early experience in the Shiite Amal militia. But he broke away from Amal in 1982 along with several other colleagues in a dispute over ways to confront the situation resulting from the full-scale Israeli invasion of Lebanon.

He was elected secretary-general of Hezbollah in 1992, aged just 32, after an Israeli helicopter gunship killed his predecessor Abbas al-Musawi in southern Lebanon.

Hezbollah's resistance to Israel's 'Grapes of Wrath' military offensive in Lebanon in 1996 cemented Nasrallah's role as a symbol of resistance and secured him a privileged place with Syria, where his portrait is omnipresent.

He acquired cult status in Lebanon and across the Arab world after Israel withdrew its troops from southern Lebanon under relentless Hezbollah attack in May 2000, ending 22 years of occupation in the region.

Nasrallah's 14 years at the helm of Hezbollah, or Party of God, have also been marked by internal successes in Lebanon.

It has 14 MPs in the Beirut parliament, and until a walkout in November 2006 also held two cabinet posts.

Hezbollah is admired by many Shiites in Lebanon for supporting local charities and for assisting many of those displaced in the 2006 war.

Nasrallah's popularity soared after a UN-brokered ceasefire ended the conflict on August 14, 2006, with supporters handing out posters bearing his photograph and declaring 'divine victory.'

The Hezbollah chief is married and has several children. His eldest son Hadi was killed during a military operation against Israeli troops in southern Lebanon in 1997. -AFP