A bomb attack killed at least 5 people and wounded 40 at the funeral for a Shi'ite Muslim on Friday in the northwest Pakistani town of Dera Ismail Khan.
The attack sparked an outbreak of shooting around the hospital where the dead and wounded were brought, and police fired tear gas in an attempt to restore order, according to journalists at the scene.
NWFP Information Minister Mian Iftikhar Hussain told Reuters 10 people were killed and up to 30 wounded, though a doctor at the main government hospital put the number of wounded at 40.
The funeral was for a man killed on Thursday, but a Shi'ite cleric was also killed on Friday morning before the funeral.
"One of our men was martyred yesterday and one today. We were taking the coffin to the graveyard, reciting mourning hymns, when suddenly this blast happened," Tauqir Zaidi, one of the mourners, told Reuters by telephone from the hospital.
Witnesses gave conflicting accounts on whether the blast was caused by a suicide bomber or a device planted on the funeral procession's route.
Sectarian violence between militant Sunni Muslim and Shi'ite groups has plagued Dera Ismail Khan, a district bordering the South Waziristan tribal region, where support runs deep for the Taliban and al Qaeda.
A suicide bomber targeted a Shi'ite protest against the killing of one of their community leaders in Dera Ismail Khan on Aug. 19, killing 23 people.
Both the Taliban and al Qaeda are Sunni, and some of their cohorts, like Laskhar-e-Janghvi, are rabidly anti-Shi'ite.
The majority of Pakistan's Muslims are Sunni, but around 15 percent of the 170 million nation are Shi'ite.
Thousands of people have been killed in tit-for-tat sectarian violence going back to the 1980s, and earlier this year around 200 people were killed in fighting between Sunni and Shi'ites in the Kurram tribal region