The assassination of a provincial lawmaker in a suburb of Karachi has sparked violence across Pakistan's largest city that has claimed at least 35 lives and injured 127 others, Press TV reported.
On Monday, Raza Haider, 35, a senior leader of the Muttahida Qaumi Movement (MQM) and a member of the Sindh Assembly, was assassinated by unknown gunmen in a drive-by shooting at the Jama Masjid in Nazimabad, where he had gone to attend the funeral of the mother of a friend.
His police guard was also killed.
Arson attacks and intense gunfire are continuing in various parts of the city and there could be a severe backlash, police officials said early on Tuesday morning.
Over 20 vehicles and a number of restaurants and shops were set on fire.
"The number of attackers and the mode of their transport are not clear, but initial investigations suggest that there were more than two people who came on a motorcycle and were probably backed by armed men in a car," said an officer at the Nazimabad police station.
"They first shot at the legislator's guard Khalid Khan and then entered the mosque and fired at Haider, who was in the ablution room," he added.
They were shot at close range, and each man received a bullet in the head and another on the upper part of the body.
The police said that an AK-47 rifle and a 9mm pistol were used in the attack and the spent cartridges were found at the scene.
The MQM leadership has put the blame on the Awami National Party, an ally in the Pakistan People's Party-led coalition government in Sindh province.
There have also been violent protests in Hyderabad and Mirpurkhas.