Political and ethnic rivalries and turf wars — sometimes linked to criminal gangs — make it difficult to maintain order in Karachi, home to Pakistan’s main port, stock exchange and central bank and the main gateway for Western military supplies bound for neighbouring landlocked Afghanistan.

The killings began on Saturday, ahead of a byelection to replace a provincial lawmaker murdered in August, raising fears of a new bout of instability in the city.

The Muttahida Qaumi Movement (MQM), a partner in the coalition government of President Asif Ali Zardari’s Pakistan People's Party, says its workers are among those killed and called for the day of mourning.

Four people were killed in different incidents on Wednesday, after 19 were gunned down a day earlier, including 10 in a single attack in the Sher Shah area, known locally for used cars and machine parts.

No govt

“It seems that there is no government in Karachi,” Altaf Hussain, the leader of the MQM, said in a statement from self-imposed exile in London. “The government has failed to protect the lives and properties of the people of Karachi.”

The violence has led to calls from different politicians for the army to enter Karachi to help stem the violence, which has seen hundreds of people killed this year.

The MQM has been threatening to pull out of Zardari’s coalition, a move which could lead to the government losing its National Assembly majority or even its downfall if the MQM sides with the opposition.