A mob, angered over the recent rape and murder of an eight-year-old girl, attacked a police station and a nearby government building in eastern Punjab province on Wednesday, triggering clashes that left at least two people dead and several injured.
The violence erupted in the city of Kasur hours before the funeral of Zainab Ansari, whose case has drawn wide public outrage.
The girl went missing last week while going to a nearby home for Quranic studies. Her parents, who were away at a pilgrimage in Saudi Arabia at the time, returned on Wednesday, landing at Islamabad airport.
"We will not bury our daughter until her killers are arrested," said the father, Ameen Ansari, as his wife sobbed.
Zainab's body was found on Tuesday in a rubbish bin, said senior police officer Imran Nawaz Khan. Police say she was abducted, raped and murdered. Officer Maqsood Ahmed said six girls have been sexually assaulted in recent months in Kasur and police are examining the cases to see whether they are connected.
Activists on social media have castigated the government for failing to arrest those involved in the crime.
Nobel Peace prize winner Malala Yousafzai, condemned the murder of Zainab, saying "such brutal incidents have to stop."
As the attack on the police station and the subsequent clashes unfolded on Wednesday, local television broadcast footage showing police firing shots into the air and towards the stone-pelting mob, trying to disperse it. In one segment, an officer asks another to hold direct fire, after which the second officer is seen continuing to shoot at the protesters.
Also on Wednesday, the chief justice of the High Court in Lahore ordered an investigation into the killing of Zainab.
Zulfiqar Hameed, the police chief in Kasur, refused to say whether the two people killed in Wednesday's clashes had died from police gunshots. Provincial law minister Rana Sanaullah said the police were trying to contain the violence and to find and arrest those involved in the girl's murder.
Kasur shop owners shut their businesses on Wednesday to express their anger over Zainab's slaying.
Firebrand cleric Tahir-ul-Qadri who took part in her funeral service demanded the local government be replaced, saying, "It has no right to remain in power after the killing of Zainab Ansari."
In a speech to thousands of mourners, he blamed the Punjab chief minister, Shahbaz Sharif, for failing to "protect lives and honuor of innocent girls" in the province. Mr Qadri also issued an ultimatum to Sharif and Sanaullah to step down by January 17 to avoid street protest.
Mr Qadri is a staunch political rival of the ruling Pakistan Muslim League party and he has led violent rallies in the capital, Islamabad, since 2014 after eight of his supporters were killed in anti-government rallies in Lahore, Punjab provincial capital.