Hezbollah chief Hassan Nasrallah has said he is ready to fight 'radical' Muslims in Syria, a day after a deadly bombing in a Beirut suburb left many dead.

Nasrallah in his speech on Friday also accused Sunni 'extremists' of responsibility for the car bombing that killed at least 22 people.

"I will go myself to Syria if it is so necessary in the battle against the takfiris [radical Sunni Muslims]," he said defiantly.

In the speech broadcast on television as Lebanon held a day of mourning for the victims of the bombing, Nasrallah said that Thursday's bombers "are not Sunnis, they are assassins", and accused them of seeking to drag Lebanon into 'civil war'.

Shortly after the attack, a video belonging apparently to the Sunni group Aysha Umm-al Mouemeneen surfaced on the web to claim responsibility.

It showed three masked men, two of them holding rifles, in front of a white flag inscribed with the Islamic profession of faith.

"We ... send a message to [Hezbollah chief] Hassan Nasrallah's pigs," said one of the men, wearing a white mask.

Hezbollah is a supporter of Syrian President Bashar al-Assad and has sent fighters across the border to Syria this year to bolster government forces, who have been battling an uprising since March 2011.

Thursday's blast came six weeks after a car bomb attack in the same area wounded more than 50 people.

Nasrallah said the attacks would not weaken his resolve to support the Assad government. 

"If you think that by killing our women, our children and innocent people, by destroying our neighbourhoods, we will withdraw [support of Assad], you are fooling yourselves," Nasrallah said.

Source: Agencies