Tens of thousands of Shiite Muslims marched to a martyrs' burial ground on Thursday to lay to rest 32 victims of an attack on a religious procession earlier this week, many wailing in anguish and demanding top officials resign for failing to stop the killings.

Suspicion for Tuesday's attack in the southern city of Quetta has fallen on Lashkar-e-Jhangvi, a Sunni Muslim militant group with suspected ties to Al Qaeda (search). The group also is believed responsible for a July 4, 2003, attack on a Shiite mosque in Quetta that killed 50.

"Our enemies are not hidden. They are Sipah-e-Sahaba and Lashkar-e-Jhangvi," a Shiite leader, Haji Abdul Qayyum, said. Sipah-e-Sahaba is Pakistan's other main Sunni extremist group, believed to be behind the killing of hundreds of Shiites in recent years.

Many in the crowd chanted for the death of the city's anti-terrorism chief for failing to prevent the attack, which killed 43 people, including six policemen and two of the attackers. Three victims have not been identified.

Authorities say there is no evidence of a link between Tuesday's Quetta attack and deadly bombings less than two hours earlier in Iraq that also targeted Shiites. Both attacks occurred on Ashoura, a day when Islam's Shiite faithful mark the death of a revered 7th-century leader by marching in black and lashing themselves in penitence.

The 32 victims were buried in a walled section of a Shiite graveyard on the eastern outskirts of Quetta. The section is reserved for members of the sect considered to have been martyred, including the victims of other acts of sectarian violence in the city.

Security was tight during the funeral, with sharpshooters positioned on rooftops, but no violence was reported.

The funeral had been delayed by a day as Shiite leaders pressed for the resignation of the mayor, police chief and head of the anti-terrorism force they blame for security lapses. None of the men has stepped down.

Quetta remained under a curfew Thursday to prevent further violence, with soldiers in armored personnel carriers patrolling the streets. After Tuesday's attack, enraged Shiites targeted a Sunni mosque and shops in retaliatory rioting.

Lashkar-e-Jhangvi is closely linked to Afghanistan's former rulers, the Taliban militia, and is believed to have hidden members of the Al Qaeda terror network after the Sept. 11, 2001, attacks in the United States. The group also has been implicated in the 2002 slaying of Wall Street Journal reporter Daniel Pearl and numerous church and bus bombings.

Three suspects hurled grenades and fired shots into the religious procession, then detonated grenades and explosives strapped to their bodies. One of the suspects survived and is in critical condition.

A government official, who spoke on condition of anonymity, said "medium intensity explosives" were used in Tuesday's attack, although it was not immediately clear what kind.

Although most of Pakistan's Sunnis and Shiites live peacefully together, small radical groups on both sides are responsible for frequent attacks. All but 3 percent of Pakistan's people are Muslim, and Sunnis outnumber Shiites 4-to-1.