More than 700 reports of disappearances have been received by the United Nations from Pakistan, and hundreds more have been reported to Pakistani authorities, but nobody has ever been held accountable for an enforced disappearance in the country, Amnesty International says.

"The UN Working Group on Enforced or Involuntary Disappearances has more than 700 pending cases from Pakistan, and Pakistan's State Commission of Inquiry on Enforced Disappearances has received reports of hundreds more, from across the country," Amnesty said in a statement on March 19.

"Victims include bloggers, journalists, students, peace activists, and other human rights defenders whose work promotes the same values as this [UN Human Rights] Council and is crucial to a free and just society," the statement said.

"No one has ever been held accountable for an enforced disappearance in Pakistan," it said.

The London-based rights watchdog said that the disappeared risk torture and even death, and called forced disappearances "a tool of terror."

The Amnesty statement warns Pakistani authorities that forced disappearances are a crime under international law and qualify as a crime against humanity if committed on a systematic and widespread basis.

The watchdog notes that disappearances occur in Pakistan amid a larger-scale campaign against civil society.

"Freedom of expression is criminalized online. Human rights defenders are smeared and threatened and journalists are attacked. Civil society organizations are subject to greater restrictions, and international NGOs have been expelled," Amnesty said.

The group welcomed Islamabad's acceptance of international recommendations to declare enforced disappearance a criminal offense, but voiced disappointment over "Pakistan's failure to accept several recommendations -- including from states with their own traumatic history of disappearances -- to ratify the International Convention for the Protection of All Persons from Enforced Disappearance."