KARACHI: Director General (DG) Rangers Major General Bilal Akber accepted that the deceased MQM worker was tortured by Rangers in custody and vowed that strict action will be taken against those responsible for misconduct.

Talking to DawnNews on Tuesday night, Akbar accepted that Aftab Ahmed was tortured during custody and the standard operating procedures were not followed by some Rangers personnel in this case.

The DG Rangers assured that strict action will be taken against those responsible for this misconduct but maintained that Aftab's death had occurred due to a heart attack.

The statement comes after pictures and videos were seen doing rounds on the social media, reportedly showing the corpse of the deceased MQM worker having major torture marks across his body.

Earlier in the day, a Mutahidda Qaumi Movement (MQM) leader claimed that Aftab Ahmed, said to be the coordinator of senior MQM leader Dr Farooq Sattar, died in the custody of Rangers.

"Aftab Ahmed died during Rangers custody as he was detained for 90 days for no reason," MQM spokesperson Wasay Jalil said in a tweet.

The Rangers later said in a press release that Aftab had complained of chest pain early morning, after which he was taken to the hospital.

Dr Seemin Jamali, head of emergency at JPMC, said Ahmed, who the Rangers picked up in a raid on Sunday, was admitted to the hospital at around 7am on Tuesday.

Cardiopulmonary resuscitation (CPR) was performed on the man, who had no pulse and no blood pressure when he was brought to the hospital, she said.

He died at around 7:45am after doctors failed to revive him, she said.

Additional police surgeon Dr Kaleem Shaikh said the exact cause of his death would be ascertained after post-mortem.

"The death in custody is a cause for concern and we want a transparent investigation into the matter," Farooq Sattar told DawnNews.

The postmortem was conducted in the presence of a magistrate but the exact cause of death was reserved, said a hospital official.

Meanwhile, Leader of the Opposition in the Sindh Assembly MQM's Khawaja Izhar-ul-Hassan demanded formation of a commission to investigate Aftab Ahmed's death, saying "responsibility should be fixed for his death in custody".

The Pakistan Rangers had informed on Monday the administrative judge of antiterrorism court about 90-day preventive detention of seven suspects, including Aftab Ahmed, for questioning.

The paramilitary soldiers along with their legal team produced the detainees before the judge along with intimation applications, detention orders and jail warrants.

They informed the court that upon receiving credible information about their involvement in targeted killing, kidnapping and extortion punishable under the Anti-Terrorism Act 1997, they were put under three-month preventive detention as provided in Section 11-EEEE of the ATA for an inquiry.

For a little over a year, MQM has been under the spotlight when it comes to the Rangers-led Karachi operation. In March 2015, Rangers personnel detained a number of MQM workers, including senior members such as Amir Khan, in a pre-dawn raid on the party's headquarters.

The raid, which prompted a protest by party activists, appeared to have symbolic significance in the operation that has been underway in Karachi since October 2013.

Most recently, Rangers arrested MQM Rabita Committee Deputy Convener Shahid Pasha in a raid on his residence last month.