A woman and two children walk through a slum neighborhood of Karachi, Pakistan. In this violent city of 18 million people, business leaders have called for the army to intervene to restore order. Even during the month of Ramadan, a time of piety for Muslims, violence has surged, as gangs tussle over forced charitable funds.

KARACHI, Pakistan — Warring ethnic gangs have turned Karachi, Pakistan’s largest city and the country’s commercial capital, into a battle zone with death squads unleashing gruesome torture on ordinary citizens at a rate that far outstrips the much better publicized violence attributed to al-Qaida-linked extremists.

More than 1,000 people have been killed here this year, as many as half of those in July and August in a murderous frenzy that has grown worse in recent days.

Across the city, corpses turn up dumped in sacks, the marks on the bodies inside a testimony to the agonizing death they have endured. Notes attached to some corpses read, “Do you want war or peace?”

The victims can be anyone from a rival ethnic group, making the killing horrifyingly random. In August, gangs took to hijacking buses, checking the identities of male passengers and taking away those from other racial groups. They would later be found in sacks.

Muhammad Kashif, a 30-year-old ambulance driver with Edhi, a charity that runs most of the ambulance service for the city, said the bodies he picks up from gutters and alleyways are blindfolded with their hands and feet tied.

“Some have their heads severed. Some have the heads but the ears, noses, tongues have been cut out. Eyeballs are sticking out. Arms are broken, legs are broken,” said Kashif, who’s based at Karachi’s Civil Hospital.

“The victims are just people who were going to work, not gang members,” he said. “For ordinary people, there’s no safety.”

Edhi alone collected 221 bodies off the streets from gang-related violence in July. It had collected 125 more in the first 19 days of August.

Police privately admit to being helpless bystanders, unable and unwilling to intervene in a fight that’s political, with three mainstream parties representing different ethnic groups and their gangs. Last week the provincial government announced a police operation against the gangs, but so far it has yielded only two dozen arrests. Police officers weren’t able to enter some of the most violent neighborhoods.

The violence worries U.S. officials, who fear the violence in Karachi could cripple not just Pakistan’s already weak economy but hamper getting supplies to U.S. troops in Afghanistan.