Some of those freed by Pakistani military and intelligence agencies had been charged with links to terrorism, The New York Times reported, quoting human rights groups and lawyers who had been demanding to bring their cases to trial.
The report said those released are among the 500 or so Pakistanis who may have been taken by Pakistani intelligence agencies working with the U.S. war against terrorism.
Their release may indicate the government wants to avoid being accused of holding such prisoners on flimsy evidence in a secret system, opponents of the prison told the Times.
The government rebuffed allegations of illegal detention, saying many of those reported to have disappeared are in regular jails on criminal charges and dismissed other cases as fabrications, the report said. U.S. officials in Pakistan and Washington declined comment.
Human rights groups claim the government has used the excuse of fighting terrorism to round up at least 4,000 others, most of them Balochis and Sindhis who have been demanding autonomy.