Pakistan: MQM activist arrested over Karachi riots
A local leader of Pakistan's MQM party has appeared in court accused of involvement in violence in Karachi in 2007 which killed at least 45 people.
Rafiq Rajput was arrested on Sunday and will be held in detention for 90 days.
While in custody he will be questioned further by Rangers paramilitaries, who say he has confessed.
However, a senior MQM official denied that Mr Rajput was a criminal, saying that he was a "dignified and honest man" who should not have been arrested.
His detention follows a report submitted by the Rangers which found that MQM (Muttahida Quami Movement) was responsible for a September 2012 factory fire which killed more than 250 people.
The party has rejected the allegations.
The BBC's M Ilyas Khan in Islamabad says it appears the authorities have turned on the pressure on MQM in a bid to control militancy in Karachi.
It is part of its new policy to bring factional, sectarian and ethnic killings under control in the city, our correspondent says.
Since the late 1980s, successive governments have alternatively used force and appeasement to control MQM, which is understood to have a large armed wing and the ability to destabilise Karachi, he says.
Rafiq Rajput is the leader of the Mehmoodabad branch of MQM.
The paramilitaries who arrested him say he admitted to a series of killings including involvement in the violence on 12 May 2007 which was sparked by the arrival of a former chief justice who was protesting against his sacking by military ruler Pervez Musharraf.
"It is strange that he has been arrested seven years after the 12 May incident," Amir Khan of MQM's leading Rabita Committee told the Express Tribune newspaper.