A Lebanese man carries an injured woman at the scene of an explosion in Beirut, Lebanon, on Friday, Dec. 27, 2013.

By BASSEM MROUE

Associated Press

BEIRUT - A powerful car bomb tore through a business district in the center of the Lebanese capital Friday, killing a prominent pro-Western politician and at least five other people in an assassination certain to hike sectarian tensions already soaring because of the civil war in neighboring Syria.

The blast, which wounded more than 70 others, set cars ablaze, shredded trees and shattered windows in a main street of the posh downtown Beirut area of five-star hotels, luxury high-rises and high-end boutiques. It sent a pall of thick black smoke above the nearby government headquarters and the seafront.

The bomb targeted the car of Mohammed Chatah, a former finance minister and a senior aide to former Prime Minister Saad Hariri, security officials said. Chatah, his driver and four others were killed, the National News Agency said.

Hariri, a Sunni politician, heads the main, Western-backed coalition in Lebanon, which is engaged in bitter feuding with the militant Shiite Hezbollah group, a top ally of Syrian President Bashar Assad.

The bombing recalled a string of assassinations of members of the anti-Syrian Hariri camp between 2005 and 2008, starting with a massive suicide bombing in 2005 in downtown Beirut -- not far from the site of Friday's blast -- that killed Hariri's father, Rafik, also a former prime minister. Hariri's allies accused Syria of being behind the killings, a claim Damascus denied.

More recently, the country has seen a wave of violence as Lebanon's Sunni and Shiite communities line up with their brethren on opposing sides in Syria's civil war. That has fueled predictions that Lebanon, still recovering from its 15-year civil war that ended in 1990, is on the brink of descending into full-blown sectarian violence.

There has been a series of bombings in districts dominated by Hezbollah, apparently in retaliation for its decision to send guerrillas to fight alongside Assad's forces against rebels, as well as twin car bombings in Tripoli, Lebanon's largest city and a Sunni stronghold. There have also been repeated clashes between Sunnis -- who largely back Syria's rebels -- and Shiites and Alawites who back Assad.

The last such assassination in Lebanon was in Oct. 19, 2012, when a car bomb assassinated Lebanon's top intelligence chief, Wissam al-Hassan. Al-Hassan, a member of Hariri's security circle, was a powerful opponent of Syria's influence in Lebanon and many here blamed his killing on Syria.

The Friday morning blast was heard across the city, shattering the calm of the downtown commercial district.

"We heard an explosion that shook us like an earthquake," said Wajdi Abdul-Khaliq, a foreman at a nearby construction site. The man said he ran out of the site and saw the wounded in the street, including a woman in her car who lost her hand.

The army cordoned off the area to prevent people from getting close to the scene, where the twisted wreckage of several cars was still smoldering. The National News Agency said the explosion was the result of a car bomb, but security officials said they had no immediate confirmation.

Footage broadcast on Lebanese TV showed medical workers rushing the wounded to ambulances. At least two bodies could be seen lying on the pavement. The Health Ministry said more than 70 people were wounded.

Security officials said Chatah was on the way to a meeting at Hariri's downtown residence when the bomb hit. They spoke on condition of anonymity because they were not authorized to talk to the press.

The 62-year-old Chatah was a prominent economist who once worked at the International Monetary Fund in the U.S. and later served as Lebanese ambassador to the U.S. He was one of the closest aides of Rafik Hariri.

He later became finance minister when Saad took over the premiership, and stayed on as his senior adviser after he lost the post in early 2011.

Friday's blast came less than three weeks before the trial for those suspected in Rafik Hariri's assassination was set to begin. Five Hezbollah members have been accused of involvement in the killing. Hezbollah rejects the accusations, and has refused to hand over the suspects.

Hariri's 2005 assassination sparked massive demonstrations that eventually led to the withdrawal of Syrian troops from Lebanon, following nearly three decades of military presence and domination of its smaller neighbor.

Chatah was a moderate Sunni politician who opposed Hezbollah and Assad.

His last tweet, posted an hour before Friday's explosion, read: "Hezbollah is pressing hard to be granted similar powers in security & foreign policy matters that Syria exercised in Lebanon for 15 yrs."

Associated Press writers Ryan Lucas and Zeina Karam contributed to this report.