A former prime minister of Lebanon, Saad al-Hariri, is accusing Hizbollah of being involved in the assassination of the former finance minister Mohamad Chatah by car bomb in Beirut.
The state news agency NNA said Mohamad Chatah was among several people killed and more than 50 wounded by the blasts in the capital on Friday.
Mr Chatah, who was 62 and a leading figure opposing the regime of Syrian president Bashar al-Assad, was on his way to attend a meeting at Mr Hariri's residence.
Although no group has come forward to claim responsibility, a Hizbollah parliamentarian condemned the explosion as a "terrorist act".
The ABC reports that the blast was heard across the city at about 9:40am on Friday and a plume of black smoke could be seen rising in the downtown business and hotel district.
Mr Chatah was Lebanon's envoy to Washington under Rafik al-Hariri, who was also killed in a car bombing in 2005. The ABC reports that the trial of five suspects in his assassination is due to open in The Hague next month.