Mohamad Chatah, a former Lebanese finance minister and ambassador to the United States, was killed Friday when a car bomb struck his convoy in Beirut.
The blast — which went off at 9:40 a.m. — also killed at least five other people, wounded more than 70 others, and set nearby cars ablaze and shattered windows on a main street of the city's posh downtown area.
Chatah was attending a meeting with fellow leaders of the March 14 coalition, a group of Sunni, Druze and Christian political parties. Four of Chatah’s aides were killed alongside him.
One local described the scene as chaotic, saying by phone from Beirut, “There is destruction everywhere. So much death! People in the city are lost.”
Police blocked roads throughout the capital for several hours following the blast as shops and offices closed throughout the downtown area. Many upcoming New Year’s celebrations have already been canceled following the blast as fear of more counterattacks escalates.
No one immediately claimed responsibility for the assassination.
US Secretary of State John Kerry condemned the bombing, labeling it an "abhorrent terrorist attack."
He called Chatah's killing an "assassination" and praised the slain Lebanese diplomat as a "voice of reason, responsibility and moderation."
"His presence will be missed, but his vision for a united Lebanon, free from sectarian violence and destabilizing interference, will continue to guide our efforts," Kerry said. He added that the United States would back Lebanon if it chose to pursue "those responsible for this heinous and cowardly attack."
The bombing is almost certain to hike sectarian tensions already soaring over the civil war in neighboring Syria, with Lebanon's Sunni and Shia communities lining up with their brethren on opposing sides.
Former Prime Minister Saad al-Hariri accused the Lebanese militant group and political party Hezbollah of involvement, calling the attack "a new message of terrorism."
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"As far as we are concerned the suspects ... are those who are fleeing international justice and refusing to represent themselves before the international tribunal," he said.
The 62-year-old Chatah had been at odds with Hezbollah, and had accused the group of trying to take control of the country in a tweet less than an hour before Friday's blast.
Chatah also staunchly opposed Syrian President Bashar al-Assad, whom Hezbollah has been supporting by sending weapons and ground troops across the border.
His killing happened three weeks before the long-delayed trial of five Hezbollah suspects indicted for the 2005 bombing that killed former Prime Minister Rafik al-Hariri, Saad's father, and 21 other people.
Over the past six months, a series of what appear to be retaliatory bombings have targeted both Sunni and Shia groups in Beirut and Lebanon’s second biggest city Tripoli. Just last month, 23 people were killed in twin blasts that targeted the Iranian embassy in Beirut.
The Abdullah Azzam Brigades, a Sunni jihadist group, claimed responsibility for the embassy bombing, warning via Twitter that more attacks would follow unless Hezbollah and Iran stoppped supporting the Syrian regime.
Damascus on Friday rejected accusations from the March 14 group that it had a hand in the Beirut bombing.
"These wrong and arbitrary accusations are made in a context of political hatred," said Syria's Information Minister Omran al-Zohbi, in remarks published by state news agency SANA.
"Some figures in Lebanon have never stopped accusing (Damascus) every time a painful assassination takes place in the brother country Lebanon," Zohbi added.