At least 27 people have been killed in a suspected suicide bomb attack and in subsequent violence at a religious procession in north-west Pakistan.
The explosion tore through a crowd of Shia Muslims marking the Ashura festival in the town of Hangu, sparking rioting among pilgrims.
Pakistan has a history of tension between Shia and Sunni Muslims.
Five people also died in Sunni-Shia fighting in Herat, western Afghanistan, on Thursday, doctors said.
Gunfire
The explosion in Hangu, in Pakistan's North-West Frontier Province, struck a bazaar as hundreds of people walked in a procession from the main Shia mosque in the town.
The army has sent in troops and a curfew has been imposed. No-one has claimed responsibility for the attack.
"We thought the bomb was detonated by remote control, but now it appears to be a suicide attack," local police chief Ayub Khan told the Associated Press news agency.
Police say another 22 people were taken to hospital in nearby Kohat.
Maulana Khurshid Anwar, a leader of the Shia procession, said the explosion had happened just as he was about to address the crowd.
District administrator Ghani ur-Rehman said the ensuing violence had destroyed 60% of the town's bazaar.
There are several reports of gunfire and possible fatalities following the blast, but the exact number of people who died is unclear.
Cleric's appeal
A judicial inquiry into the attack has been ordered, officials say.
Mr ur-Rehman said the situation had been brought under control by early afternoon, with Sunni and Shia religious leaders helping to calm the situation.
Shia cleric Allama Mehdi Najfi told AP from his base in Quetta in the south-west: "This attack has spread anger among our people throughout the country, but I appeal them not to clash with any member of other sects."
About 3,000 Shias protested on the streets of Karachi over the killings.
In Herat, Afghanistan, five people were killed and 27 hurt in clashes at a Shia procession for Ashura, doctors said.
PHOTO CAPTION
Pakistani policemen walk past beside a burning shop in the northwestern town of Hangu, following an attack on a Shiite Muslim procession marking Ashura. (AFP)
BBC