At least five people were killed, including Lebanese former Finance Minister Mohamad Chatah, and more than 50 were injured in a car-bomb blast Friday in central Beirut, the National News Agency reported.
Ten nearby buildings suffered significant damage in the explosion, the NNA said.
Local media said the attack targeted former Sunni Prime Minister Saad Hariri's mansion, where a meeting had been scheduled of the March 14 coalition that opposes Syrian President Bashar al-Assad's government and sympathizes with the Syrian opposition.
Outgoing Lebanese Prime Minister Najib Mikati called an emergency Cabinet meeting in response to the bombing, according to the NNA.
Chatah, 62, was Hariri's finance minister during his 2009-2011 tenure as prime minister. He had previously served as Lebanon's ambassador to the United States from 1997 to 2000.
The Shiite political and militant group Hezbollah on Friday issued a statement denouncing the car-bomb attack and calling it a "heinous crime" aimed at "sabotaging stability and national unity."
The group issued a call for "rationality and wisdom to combat the threats that weigh on the country" and urged the security forces and the courts to "find those responsible for this criminal act and bring them to justice."
Minutes before that statement was released, Hariri accused Hezbollah of being behind the attack.
"Those who killed Chatah are the same who killed Rafic Hariri," the erstwhile prime minister wrote on social media, referring to the five members of Hezbollah indicted in the 2005 assassination of his father, a business tycoon who served as Lebanon's prime minister from 1992 to 1998 and again from 2000 to 2004.
Hezbollah denies any involvement in Hariri's assassination and refuses to hand over the suspects.
Several deadly terrorist attacks have been carried out in Lebanon in recent months targeting the security forces and positions of Hezbollah, which supports the Syrian government.
Security has deteriorated in Lebanon since the start of the Syrian armed conflict in March 2011, with an increase in sectarian violence, homicides and kidnappings. EFE