About 40 people have been killed and more than 70 injured in violent clashes between Sunni and Shia Muslims in northern Pakistan.
The town of Parachinar was placed under curfew on Friday as troops were deployed to restore order.
Officials said the soldiers had been given the order to shoot-on-sight in an attempt to control the violence.
"So far we have received reports that 40 people have been killed in clashes in two days of fighting between two religious groups in Parachinar," Arif Habib, a local security official, said on Saturday.
Parachinar, a tribal town close to the Afghan border in Pakistan's North West Frontier Province, has a history of sectarian violence between its Sunni and Shia communities.
Sahibzada Anees, a local official, said soldiers supported by helicopter gunships were patrolling the streets of the town, which has a population of around 70,000.
Fourteen people were reportedly killed when rockets crashed into a house early on Saturday. Two women and four children were among the dead.
He said the violence began after members of the Shia community staged a demonstration outside their mosque protesting against local Sunnis who had allegedly chanted anti-Shia slogans during a religious rally last week.
Last year, clashes between the two communities resulted in the deaths of around 20 people.
Shias, who make up just 20 per cent of Pakistan's population of 160 million, are in the majority in Parachinar.
Sectarian violence is believed to killed more than 4,000 people in Pakistan since the late 1980s.