Pakistan's military and intelligence agencies have quietly set free nearly 100 men suspected of links to terrorism, few of whom were charged, a media report said on Wednesday.

Those released are among the nearly 500 men presumed to have disappeared into the hands of the Pakistani secret agencies cooperating with Washington's fight against terrorism since 2001, the report quoted human rights groups and lawyers in Islamabad as saying.

Pakistan's intelligence agencies, which are apparently trying to avoid acknowledging an elaborate secret detention system, warned detainees not to speak to anyone about their detention, yet fragments of their experiences have filtered out through relatives and their lawyers, the report said.

No official reason has been given for the releases, but as pressure has mounted to bring the cases into the courts, the government has decided to jettison some suspects and spare itself the embarrassment of having to reveal that people have been held on flimsy evidence in the secret system, the New York Times reported.

A few even appeared in court and told their stories, and it became increasingly clear that the 'disappeared' men had in fact been held in military or intelligence agency cells around the country, often for several years without being charged.

In one case, a suspect tied to, but not charged with the 2002 killing of Daniel Pearl, the American journalist, was dumped on a garbage heap, so thin and ill he died 20 days later. He, like one other detainee, was arrested in South Africa several years ago and released in Pakistan this year, it said.

Interviews with lawyers and human rights officials in Pakistan, a review of cases by The New York Times and court records made available by the lawyers show how scraps of information have accumulated over recent months into a body of evidence of the detention system.

The Pakistani government, the paper says, denies detaining people illegally and contends that many of the missing are actually in regular jails on criminal charges, while other cases have been fabricated.

In at least two instances, detainees were handed over to the US without any legal extradition proceedings, it said, quoting Pakistani lawyers and human rights groups.

American officials in Islamabad and in Washington refused to comment on the cases, it said.

"They are releasing them because these cases are being made public," Shaukat Aziz Siddiqui, a lawyer working at the Supreme Court who has taken many cases of the missing, told the paper, adding, "They want to avoid the publicity."

In addition, human rights groups and lawyers in Islamabad contend, the government has swept up at least 4,000 other Pakistanis, most of them Baluchi and Sindhi nationalists seeking ethnic or regional autonomy who have nothing to do with the United States campaign against terrorism.

Human rights groups and lawyers, it says, describe the disappearances as one of the grimmest aspects of Pervez Musharraf's [Images] presidency, and one that shows no sign of slowing.

Under previous governments 'there were one or two cases, but not the systematic disappearances by the intelligence agencies under Musharraf,' Iqbal Haider, secretary general of the Human Rights Commission of Pakistan, an independent nonprofit organisation, told the Times.

The issue of the missing became one of the most contentious between President Musharraf and the Supreme Court under its former chief justice, Iftikhar M Chaudhry, it notes.

The releases, the Times says, are particularly galling to lawyers because as one justification for imposing emergency rule on November 3, President Musharraf accused the courts of freeing terrorism suspects. That decree was lifted Saturday, but the former chief justice and other judges were dismissed and remain in detention. The Supreme Court hearings on the missing have been halted.

While Musharraf criticized the court as being soft on terrorists, it says court records show that Chaudhry was less interested in releasing terrorism suspects than in making sure their cases entered the court system.

He said at each hearing his primary concern was for the families of the missing, who were suffering anguish not knowing where their loved ones were.

"Not a single person who was convicted was released on the Supreme Court's order," Siddiqui said.

The director of the human rights commission I A Rehman said the government had set up a nearly invisible detention system.

"There are safe houses in Islamabad where people are kept," he said, citing accounts from the police and freed detainees. "Police have admitted this. Flats are taken on rent; property is seized; people are tortured there."

In some cases, detainees recounted that they had been interrogated in the presence of English-speaking foreigners, who human rights officials and lawyers suspect are Americans, it says.