Mourners gathered Sunday for the funeral of a top intelligence official whose assassination in a bombing blamed on Syria has drawn calls for the resignation of the Hezbollah-led government from the country’s anti-Syrian alliance.

Leaders of the March 14 alliance have accused the Syrian government of killing Brig. Gen. Wissam al-Hassan, the head of the Internal Security Forces’ information department in revenge for his role in exposing Syrian-led plots to plant bombs in Lebanon. He was a close friend and ally of Sunni political leader Saad al-Hariri, a central figure in Lebanon’s anti-Syrian camp.

The country has been on edge since the Friday attack, which sent political and sectarian tensions soaring across the country after months of building friction around the crisis in neighboring Syria. Sunnis took to the streets in several areas to burn tires and block roads in protest at the bombing, which revived dark memories of a wave of similar assassinations against anti-Syrian figures in 2005-08.

A bigger test of the momentum building behind the opposition’s efforts to force the government out will be the funeral, which is taking place at the downtown location housing the tomb of Hariri’s father, former prime minister Rafiq al-Hariri. The elder Hariri’s 2005 death, also in a bombing blamed on Syria, forced Syrian troops to leave Lebanon, then plunged the country into three years of turmoil.

The March 14 coalition, named after the date of a huge rally after Hariri’s death, called on citizens to make Sunday a “day of rage” against “the butcher Bashar al-Assad and the black regime that rules Syria.”

Although Syria was blamed for this latest bombing, the opposition is focusing its attention on Syria’s chief Lebanese ally, Hezbollah, whose political and military dominance over the country is deeply resented by many Sunnis and Christians.

The March 14 statement also called for the resignation of Prime Minister Najib Mikati and his government, which it said “does nothing but implement the policies of the killer Syrian regime.”

Mikati told reporters he was ready to resign but said he had been asked by the president, Michel Suleiman, to stay on pending a resolution of the crisis.

“The government is not the issue,” he said. “The government is going to resign sooner or later. Not now, but sooner rather than later. But we don’t want to go into the unknown.”

The crisis has heightened long-standing concerns that the conflict in neighboring Syria is spreading to Lebanon, whose factions have been polarized by the revolt against Assad’s rule.

But the assassination has also revived festering grudges left unresolved by the upheaval of the past decade. The strife ended after Hezbollah fighters swept through the streets of the mostly Sunni West Beirut area of the capital in 2008, routing a fledgling Sunni militia formed by Saad Hariri and asserting the movement’s role as the country’s most powerful military and political entity.

Sunnis have not forgiven Hezbollah for using against Lebanese citizens the weapons it is permitted to possess under the terms of the 1990 peace accord that ended Lebanon’s 15-year civil war. Nor have they forgotten its conquest of areas traditionally deemed Sunni areas of influence.

Sunnis at a small protest rally organized by the March 14 coalition in downtown Beirut said the time had come to avenge both Hassan’s death and the events of 2008.

“We won’t accept humiliation anymore,” said Anis Mikati, 24, who stood with his friends under a big, black banner inscribed in white with the Islamic declaration of faith often associated with al-Qaeda. He denied affiliation with any group. “We are Sunnis, and we are ready to fight,” he said.

A group of Christians waving the banner of the Lebanese Forces, a onetime militia faction in Lebanon’s civil war, said they, too, were hoping for a fight to end Hezbollah’s hegemony.

“We hope for a war to fix this country, because Hezbollah wants to control everything,” said Ghadi Roukaiby, 16.

But the rally, held in Beirut’s vast Martyrs’ Square, was a shadow of the massive gathering there after Hariri’s death, when as many as a million people turned out. The attendance Saturday called into question how far the Lebanese are prepared to go to express their anger at a time of deepening fears that the Syrian hostilities could ignite a region-wide conflict.

The U.N. special envoy for Syria, Lakhdar Brahimi, warned of the implications of allowing the Syrian war to rage unchecked during a visit to Beirut two days before the bombing.

“This crisis cannot remain confined within Syrian territory,” Brahimi told reporters. “Either it is solved, or it gets worse . . . and sets [the region] ablaze.”

Brahimi met in Damascus on Saturday with Syrian Foreign Minister Walid Moallem to discuss his proposal for a four-day cease-fire over the Muslim Eid al-Adha holiday that begins next weekend. He made no statements, but the Associated Press reported that he would meet with Assad on Sunday.

On the eve of Brahimi’s arrival in Syria, activist groups said 84 civilians, many of them children, had died in a mass killing on the outskirts of the eastern city of Deir el-Zour. The British-based Syrian Observatory for Human Rights said 110 people were killed Saturday, including 37 members of the government security forces.

Ahmed Ramadan and Suzan Haidamous contributed to this report.