Pakistan has reimposed a curfew in the northern city of Rawalpindi, after sectarian clashes that have claimed at least nine lives, officials said.
The curfew was briefly suspended on Saturday night, but was back in place by Sunday morning, with army units patrolling the city in order to keep the peace.
On Sunday, authorities also extended a cellphone services suspension from Rawalpindi to neighbouring Islamabad, the Pakistani capital. The suspension will last until 2:00pm local time (09:00 GMT) on Sunday.
The initial curfew was imposed after at least nine people were killed and 50 wounded in sectarian clashes at a Shia Muslim religious procession on Friday.
Violence erupted at the Ashura procession as it passed by a Sunni Muslim seminary, where a cleric was delivering a sermon that marchers said was insulting to Shia Muslims. Several people within the seminary also reportedly shouted insults at the procession.
The ensuing clashes, which lasted for several hours and resulted in the burning down of the seminary and a number of shops in the area, escalated from beatings into an exchange of gunfire.
The rival groups attacked each other, TV cameramen and security forces, witnesses said.
Violence also erupted in the southern city of Multan and Chishtian town, where authorities called in troops to maintain law and order.
A senior police official in Multan told the AFP news agency that at least 12 people were injured there when Sunnis took to the streets to protest against the Rawalpindi incident, leading to clashes with Shias who fired warning shots in the air.
In neighbouring Chishtian, a Shia mosque was partially damaged and several shops were destroyed when Sunnis torched them in retaliation for the violence in Rawalpindi.
Shahbaz Sharif, the chief minister of Punjab province, of which Rawalpindi is a major city, told an official meeting after the clashes that the government should ensure those responsible for the clashes are brought to justice.
"We condemn the act of violence in Rawalpindi and sympathise with the aggrieved families. We will take the culprits to the task," he said in his statement.
But one local legislator, Sheikh Rashid Ahmed, who is a member of the lower house of the parliament, said that the violence there was the result of the local government's failure.
"I declare the local administration responsible for Friday's violent acts. They failed to control the situation," Ahmed told a news conference.
The Chief Justice of the Lahore High Court announced on Sunday that a judicial commission would investigate the circumstances around the violence.
Sectarian violence has long been a problem in Pakistan, but has escalated sharply in the last few years, with Shia Muslims, who account for about 15 percent of the population, targeted by armed groups such as the Lashkar-e-Jhangvi, the Tehreek-e-Taliban and others.
Pakistan had deployed heavy security all across the country for Ashura on Friday - which is the death anniversary of Hussein, the grandson of the Prophet Muhammad - to avert any attacks on the mourning processions.