The activist was identified as Muazzam Ali. According to sources, the arrested man is a political supporter of MQM and a local trader.
Rangers’ team raided a house of Muazzam Ali on a tip-off and shifted him to an undisclosed location for interrogation.
In a statement issued couple of hours after the arrest, MQM’s Rabita Committee said the arrested man had no affiliation with the MQM.
The paramilitary force on March 11 raided the offices of MQM, seizing a “huge quantity” of weapons and arresting activists, including one accused of murdering a journalist.
The raid on the MQM headquarters, known as “Nine-Zero”, sparked an angry response from the party, with workers shutting down large parts of Pakistan’s biggest city.
At least one supporter of the MQM, the fourth-largest party in parliament, also during the forces’ raid.