The police personnel were ambushed late on Friday night in Chakra Goth area of Korangi, but two of the gunmen were captured after being injured in the ensuing shootout.

“The policemen were in plain clothes when they were ambushed and retaliated immediately,” city police chief Saud Mirza said.

The gunmen after attacking the van disembarked the policemen and shot dead four of them before the other commandos retaliated.

“Around 35 policemen, who were wounded in the ambush, have been shifted to Jinnah hospital the condition of six is critical,” Mr. Mirza said.

The injured included a DSP from Quaidabad.

The incident took place on a day when despite President Asif Zardari chairing a high level meeting in Islamabad to discuss the law and order situation in Karachi, the violence escalated with the death toll reaching 27.

Besides the killings, there were reports of 18 people missing and gunmen opening fire on public transport in some areas.

Seven vehicles were also torched in different parts of Karachi as the death toll for two days of violence has reached around 70.

Most of the killings have been reported in the southern Lyari neighbourhood, a stronghold of the ruling Pakistan People’s Party and now infested by powerful criminal gangs.

Karachi’s worst-affected areas are impoverished and heavily populated neighbourhoods where most of the criminal gangs are believed to be hiding.

The independent Human Rights Commission of Pakistan said 800 people have been killed in Karachi so far this year, compared with 748 in 2010, but unofficially the figure of dead is said to be around 1200 with 1300 wounded.

In a disturbing trend, since yesterday, many mutilated and tortured bodies have been found in gunny bags from different parts of the city victims of apparent ethnic killings.

At least seven bullet-riddled bodies were found dumped in sacks across the city on Friday and officials said four of the victims were Urdu-speaking and were killed after having been abducted.

Officers said their hands and legs were tied and they bore several marks of torture.

There were also unconfirmed reports of 12 to 15 passengers in a bus being kidnapped in Sohrab Goth.

Beefing up the intelligence network in Karachi and working out an arrangement to allow for pursuit of criminals fleeing the city were among the decisions taken at a meeting chaired by President Asif Ali Zardari at the presidency.

Governor Sindh Dr Ishratul Ibad and Chief Minister Sindh Syed Qaim Ali Shah were among those present at the meeting.