At least 25 people have been killed in attacks by gunmen in the southern Pakistani city of Karachi, police say.
They said about 12 were killed in an attack on a car spare parts market. The rest died in a series of attacks elsewhere. All the dead are civilians.
More than 50 people have now died since violence erupted on 16 October prior to a highly charged election in the city.
Hundreds of people have died in politically motivated attacks and militant bombings since January.
Gunmen are roaming the main avenues of Karachi, targeting civilians, eyewitnesses told the BBC late on Tuesday.
Dr Karrar Abbasi, medical officer at the city's main Civil Hospital, told the BBC 12 bodies had been taken there.
Dozens of other people have been injured.
Some of the victims were shot at the famous Shershah automobile spare parts market.
The market is located in the south of Karachi, within walking distance of the city's main dockyard.
Eyewitnesses say six to seven armed men on motorbikes drove up to the market early on Tuesday evening and initially shot in the air before shooting people indiscriminately.
"I was able to get inside my shop and hid on the roof with my friend," Zeeshan - a shopkeeper who managed to escape the carnage - told the BBC's Syed Shoaib Hasan.
"They [the gunmen] continued the attack for 20 minutes before leaving."
Our correspondent says most shopkeepers in this part of the market belong to the Urdu-speaking community that traditionally supports the Muttahida Qaumi Movement (MQM), which is part of the governing coalition in Sindh province.
Violence broke out over the weekend during a by-election for a provincial assembly seat that was held by local MQM politician Raza Haider, who was murdered in August.
His death triggered riots that killed at least 100 in a city with a history of ethnic and sectarian tensions.
The violence has pitted the MQM on one side and the Awami National Party (ANP) and the Pakistan People's Party (PPP) - backed by the Pashtun and Balochi communities - on the other.
The MQM held onto Mr Haider's seat. The ANP boycotted the by-election.