Lebanon's anti-Syrian opposition have dismissed an invitation from pro-Syrian President Emile Lahoud for immediate talks to end political turmoil gripping the country.
The statement came hours after a bomb raised fresh fears of a return to the country's violent past.
"Lahoud today invites us to dialogue as though he is an independent when he is accused," Druze chieftain and key opposition leader Walid Jumblatt told reporters.
Investigators sifted through the rubble left by the blast, which wounded 11 people and gutted the ground and first floors of a residential block in a Christian suburb of eastern Beirut. Security sources said the bomb had been left in or under a car belonging to a Lebanese-Armenian man who lived in the building, but it was not clear why.
Mr Lahoud had earlier cancelled plans to attend Monday's Arab Summit in Algeria, saying the turmoil in Lebanon required him to stay.
Syria has already bowed to international demands it withdraw troops from Lebanon, after Hariri's death prompted hundreds of thousands of Lebanese to protest against the Syrians and accuse them of responsibility for the killing.
Syria denies the charge but has begun withdrawing the troops it poured into Lebanon early in the 1975-1990 civil war.
The opposition wants a neutral cabinet to lead Lebanon to elections, due in May but threatened with delay if the deadlock lasts, and an international probe into Hariri's killing, which Mr Jumblatt has accused Lebanese authorities of trying to cover up.