(CNN) -- At least 21 people died in a wave of violence in the volatile city of Karachi on Tuesday, police in Pakistan said.
Attackers struck a prominent marketplace and four other locations. Gunmen on motorbikes killed 12 people at the Kabari Market.
Rafiq Gul, a senior police official in Karachi, said it is not known whether the same group was responsible for the other strikes. At least 19 people were wounded in the violence.
At least 69 people have been killed in Pakistan's largest city over the last four days, including Tuesday's victims.
Prime Minister Syed Yusuf Raza Gilani issued a statement saying "those playing with innocent lives are surely the enemies of the people of Pakistan and the state so it is the duty of all to stand against such elements".
Gilani urged people to "sit together to resolve the issue and prepare a joint strategy to defeat the militant elements who are destroying the peace of Karachi".
Police believe recent violence in the city is connected to the assassination of a prominent politician in August.
The killings began Saturday ahead of a provincial by-election to replace the assassinated lawmaker from the Muttahida Qaumi Movement, a liberal political party whose stronghold is Karachi.
CNN
