Pakistani authorities have launched a major operation to find the abducted son of a Pakistani governor assassinated earlier this year for opposing the country's controversial blasphemy law.

Witnesses say Shahbaz Taseer was abducted in Lahore's upscale Gulberg area early Friday, when kidnappers intercepted his car and took him away in their vehicle.

No one has claimed responsibility for the kidnapping, but relatives say the Taseer family has been receiving threats from extremist groups.

Taseer is the son of former Punjab province Governor Salman Taseer, who was killed by his bodyguard in January in Islamabad after publicly supporting a woman accused of committing blasphemy.

On Friday, U.S.-based Human Rights Watch said the kidnapping of Shahbaz Taseer underscores the inability of Pakistani officials to provide security to those known to be at high risk.

The alleged assassin of Salman Taseer, Mumtaz Qadri, is on trial. He surrendered to police shortly after Taseer's death and confessed to the crime, saying he killed the governor for criticizing Pakistan's blasphemy law.

The abduction of Shahbaz Taseer is the second high-profile kidnapping in Lahore this month. About two seeks ago, American aid expert Warren Weinstein was seized at his home after eight gunmen overpowered his security guards.

Police have arrested three people suspected of belonging to the gang that kidnapped Weinstein. Authorities have also released a sketch of a suspect in the case.

So far, the kidnappers have not contacted authorities or made ransom requests.