KARACHI, Pakistan (AP) -- Riots stretched into a second day Saturday over the killing of a Sunni Muslim leader, with protesters burning cars, smashing billboards and blocking roads in Karachi, Pakistan's largest city and main commercial hub.
In the eastern city of Lahore, police used tear gas and steel-tipped batons to disperse some 300 of the slain leader's supporters, who threw stones and burned furniture to block roads near Data Darbar, a shine for a Muslim saint.
Scores of people were injured and several protesters arrested, police said.
The violence follows Friday's killing of Saleem Qadri, leader of the Muslim group Sunni Tehrik. Gunmen ambushed Qadri's van, killing him and five other companions. Qadri's 10-year-old son and two others were wounded.
Police blamed the rival Sunni Muslim group Sipah-e-Sahaba, or Guardians of the Friends of the Prophets. Sipah-e-Sahaba is one of Pakistan's most militant Sunni Muslim groups and has sharp differences with Qadri's nonviolent Sunni Tehrik.
At least 40 Sipah-e-Sahaba members were arrested overnight on suspicion of killing Qadri, said Tariq Jameel, chief of Karachi police.
Sipah-e-Sahaba spokesman Maulana Ilyas Zubair denied the group was involved in the killing.
Friday's assault occurs as Pakistan's military-led government struggles to curb the religious and political violence that kills hundreds every year in this poor South Asian country of 140 million people.
The vast majority of Pakistanis live without religious friction. But in recent years, religious violence has increased in Islamic Pakistan, where Sunni Muslims comprise the majority. Most killings result from rivalry among small but heavily armed extremist Sunni Muslim and Shiite Muslim groups.
But hard-line Sunni Muslim factions also target one another. Sunni Muslims are divided into several schools of thought, which are often at loggerheads over small religious issues such as dress or beard length.