The worst violence to hit Karachi in more than a decade is helping the Taliban to raise cash and allowing their fighters to rest in Pakistan’s largest city, The Times of London reported Thursday.

More than 300 people were murdered in Karachi last month, the majority simply because of the language they spoke. The chaos is allowing the nexus between extremist Islamist groups and criminal gangs to thrive like never before, security officials told the newspaper.

Extortion, drug, land and weapon mafias are bankrolling the insurgents, while fighters and commanders use the city to rest and gain medical treatment, according to political parties. The worst tension in recent weeks has been between the Urdu-speaking majority and Pashto-speaking migrants from the tribal regions of Pakistan.

The Pakistani government refuses to publish census data on the numbers of Pashtuns living in Karachi, but estimates range from three million to five million. Most live in illegal colonies that ring the northern outskirts of the city. The violence has created no-go areas in which Taliban fighters and commanders can operate with almost total impunity.

Overlooking Orangi Town, South Asia’s largest slum, is the notorious district of Katti Pahari, where a road has been blasted through the mountain. The intention was to create a barrier between an overwhelmingly Pashtun district and another dominated by Mohajirs, Urdu-speaking Pakistanis originating from India who make up the biggest group of the city’s 20 million population. Instead, it has become a bottleneck and shooting alley.

It was from Katti Pahari that the worst of the recent violence was unleashed in a four-day assault on the district of Malir. Naushad Asim, whose brother Mohammed, a factory worker, was murdered during it, said, “It was just after sunset when my brother went out to fix his car. He was attacked by men who were wearing beards and long hair and had camouflage jackets. They looked like Afghans.”

The bodies of gang members and political activists are dumped in sacks with their hands and feet tied -- but civilians are left where they fall, the ambulance drivers, whose job it is to clear the corpses, said.

Mohammed Raza Haroon, a leading figure in the MQM, a party that draws most of its support from the Mohajir community, denied that it was orchestrating violent retaliations. “If the MQM did not appeal for peace this city would be on fire,” he said. Although careful to avoid making overt ethnic claims, he said that its opponent, the Awami National Party (ANP), was giving shelter and support to the Taliban.

Shahi Syed, president of the ANP, an overwhelmingly Pashto-speaking organization, denied this as a smear and graphically abused the Taliban by way of proof.

Although there is no chance of the Taliban seizing the whole of Karachi, it is acting with ever greater impunity within pockets that it controls in collusion with criminal gangs. All sides agree that the insurgents and criminals are exploiting the space left by an administration and police force hamstrung by political and ethnic conflict.

“This place is going to turn into Beirut,” Syed said. “It’s dividing on ethnic grounds. We are in a dangerous position.”