BEIRUT, Lebanon - Investigators searched the rubble of a car-bombed building in Beirut for clues to an attack Saturday that boosted fears of renewed bloodshed in Lebanon and complicated already troubled negotiations between rival political groups over the formation of a new government.

The attack wounded nine people and came amid the withdrawal of Syrian troops to eastern Lebanon and Syria after a 29-year presence in this former civil war-ravaged country. The redeployments followed intense international and local opposition to Syria's role in Lebanon since the Feb. 14 assassination of ex-premier Rafik Hariri in a massive bombing that killed 17 others.

In light of the crisis, President Emile Lahoud said he will not attend Monday's Arab summit in Algeria and the army announced stricter measures against any security violators. "The army will not allow that freedom of expression be abused in order to harm security and stability," the statement by the military said.

The motive behind the bomb attack wasn't immediately clear, but it devastated an eight-story apartment building in the largely Christian New Jdeideh neighborhood shortly after midnight and sent panicked residents in their pajamas into the street.

It also played to concerns among some Lebanese that pro-Syrian elements might resort to violence to show, in their view, the need for a continued presence by Damascus forces. Hundreds of thousands of Lebanese have taken part in demonstrations for and against Syria since Hariri was killed. The anti-Syrian protests have featured large numbers of Maronite Christians.

"This has been the message to the Lebanese people for a while - to sow fear and terror among Lebanese citizens," Christian opposition member Pierre Gemayel told Al-Jazeera satellite television. The message is "if there is a Syrian withdrawal from Lebanon, look what Lebanon will face."

Police closed all entrances leading to the blast site and blocked onlookers from nearing the devastated building. After sunrise, residents began clearing debris and inspecting their damaged shops and homes.

Security officials said on condition of anonymity the blast was caused by a time-bomb placed underneath a car belonging to a Lebanese-Armenian resident of the damaged building. It was unclear where the car owner was or why the bomb was placed under his vehicle.