Prominent Pakistani human rights activist and lawyer Jibran Nasir was abducted late on Thursday night in the southern city of Karachi, his wife said, prompting a widespread outcry in the country.

No law enforcement agency has confirmed that Nasir is in their custody, but his abduction comes as the country is mired in a fresh bout of political turmoil. Mansha Pasha, Nasir's wife, said the two were driving home when they were intercepted by a white pickup truck and a sedan.

"After that, at least 15, probably more men in civilian clothing came and told Jibran to get out of the car," Pasha, a well-known actor, told Reuters on Friday, adding that all the men were armed, some with automatic weapons. She said they gave no explanation as to why Nasir was being taken.

Pasha said that she tried filing a case with the police, but they were reluctant to register it officially. A spokesman for the provincial government of Sindh did not respond to a request for comment. Nasir, who contested the 2018 elections as an independent candidate, has been an outspoken critic of multiple human rights violations in the country and represented victims as a lawyer in a number of prominent cases.

Lately, he has criticised the mass arrests of leaders from former prime minister Imran Khan's party and the move to try them in military courts following violent protests earlier this month. Rights groups say the military courts infringe on due legal process. Leading journalists have been abducted in similar circumstances, and Pakistan's powerful intelligence services are often suspected of intimidating critics in this way, though their involvement has rarely been proved.

Nasir's abduction has sparked widespread criticism on social media by journalists, activists and ordinary Pakistanis. The Human Rights Commission of Pakistan, an independent rights body, called for Nasir to be released unharmed, and for his abductors to be held accountable.