A bomb killed three people in a Christian commercial center early Wednesday, the second attack in an anti-Syrian stronghold in five days. The blast raised fears that agitators were trying to show a need for Syria's military presence in Lebanon.

A major opposition group, Qornet Shehwan (search), accused the pro-Syrian authorities of seeking to "terrorize" the people through the blasts. The local member of parliament called on his constituents to resist attempts to draw them into sectarian strife.

The explosion at the Alta Vista center in Kaslik, Jounieh, about 10 miles (16 kilometers) north of Beirut, is said to have killed a Sri Lankan and an Indian, believed to be cleaners. The bomb wounded four other people, who were treated in hospital.

A third body was found in the rubble hours later. Police said it was believed to belong to another worker from the Indian subcontinent.

The 45-pound bomb is thought to have been placed in a leather bag at the building's back entrance, said a Lebanese security official, speaking on customary condition of anonymity. A police officer received cuts from falling debris as he was inspecting the damage in the shopping center.

Lebanon has been in political turmoil since the Feb. 14 assassination of former Prime Minister Rafik Hariri (search). Mass demonstrations have forced the resignation of the government and intensified the international campaign for Syria to withdraw its troops from the country.

In Brussels, a European Union summit told Syria Wednesday it must promptly withdraw its troops and intelligence officers from Lebanon.

The 25 leaders said in a statement that Syrian President Bashar Assad (search) should "quickly implement commitments ... to remove all Syrian troops and security services from Lebanon."

The withdrawal should be carried out according to "a detailed timetable," the statement said. On Tuesday, U.N. Secretary-General Kofi Annan (search) secured a promise from Assad at the Arab summit in Algeria that Syria would produce a timetable for a full withdrawal by early April.

In Algiers on Wednesday, Annan told the Arab summit that an inquiry into Hariri's killing carried out by U.N.-appointed detectives might not be sufficient.

Annan said he expects to release a report in the next few days on the inquiry, but "I believe a more comprehensive investigation may also be necessary."

A Lebanese newspaper owned by Hariri's family has reported the U.N. team found that Lebanese authorities had tampered with evidence and were negligent in their handling of the bomb blast.

On Saturday, a car-bomb exploded in the Beirut Christian suburb of New Jdeideh, wounding nine people and causing extensive damage to an adjacent commercial and residential building.

That explosion prompted President Emile Lahoud (search) to cancel plans to attend the Arab summit currently under way in Algiers, citing the "exceptional circumstances" in Lebanon.

The intensity of the political battle over Syria's troops in Lebanon has raised fears of a return to sectarian violence of the 1975-90 civil war. So far, however, the political factions do not conform to religious boundaries, with Christians and Muslims on both sides of the debate.

But the language of the debate is fierce. On Wednesday, Qornet Shehwan issued a statement accusing "the police regime and its agents" of terrorizing Lebanon.

"They have organized attacks against some citizens and their motorcades then they moved on to a chain of explosions from Jdeideh to Kaslik," Qornet Shehwan said. The group urged people who suffered losses in the explosions to sue the interior and defense ministers for "their failure to guarantee security for the people."

The opposition lawmaker who represents Jounieh, Nematallah Abi Nasr (search), urged his constituents not to be swayed by such attacks. "Each citizen should be his own guard."

On Tuesday, about 1,000 pro-Syrian students marched on the U.S. Embassy, shouting "Death to America!" The students tore up a photograph of U.S. President George W. Bush and denounced what they said was Washington's interference in Lebanon.

The Bush administration has been at the fore of international demands for Syria to withdraw its remaining 10,000 troops from Lebanon in compliance with a U.N. Security Council resolution passed last year.

Syrian troops entered Lebanon, ostensibly as peacekeepers, in the second year of the civil war. They remained after the war, making Syria the power broker of Lebanese politics. The Beirut government and Lebanese supporters of Syria have long argued that the country needs Syrian soldiers to maintain stability.