The disappearance of hundreds of government opponents is Pakistan's most critical human rights issue, a leading campaign group there has said.
Hundreds of Pakistanis have disappeared since 2001
In its annual report, the Human Rights Commission of Pakistan said it had reports of at least 400 people believed abducted by security agencies.
The group said it had filed a petition at the Supreme Court on behalf of a number of people who have disappeared.
In the past the government has denied abusing human rights in making arrests.
War on terror
The Human Rights Commission of Pakistan's report outlined a number of human rights concerns, but said the rise in enforced disappearances over the past year was the most pressing problem.
"In the past year, unfortunately, the overall situation has been so grim," former minister Iqbal Haider, the commission's secretary general, said.
"Despite all the pleas, protests, demands from all sections of the public, including the (Supreme) Court of Pakistan, the vast majority, in the hundreds, of citizens - their whereabouts are still unknown," he said.
Mr Haider said that the country's security agencies, military and police were involved in the disappearance of Pakistani civilians, many of whom had "suffered an extreme degree of torture".
The government says those arrested are terror suspects, detained as part of Pakistan's efforts in the US-led global war on terror.
The commission's chairwoman, Asma Jahangir, said there were some terror suspects on the list of the missing, but just a few.
According to the commission, most of the disappeared were not suspected militants, rather they were ethnic nationalists from the provinces of Sindh and Baluchistan viewed as a threat by the federal government.
Ms Jahangir said that the disappearances problem was likely to be even worse than reported:
"There are a large number who don't want to come forward and there are still, we believe, a large number of cases that we do not know about," Ms Jahangir said.
"We are hoping that this will encourage more people to speak up," she said.
In the past government officials have denied unlawful arrests, but according to the BBC's Barbara Plett in Islamabad, under pressure from the Supreme Court they have been able to locate a number of missing people in army custody.
The annual report painted a grim picture of the country in general, saying there was a breakdown of institutions and of law and order.
"We see there is a dysfunctional state of affairs in the country, that nothing seems to be working. There seems to be a complete breakdown of institutions, a complete breakdown of law and order," she said.
The government has been facing a recent wave of militant and sectarian violence amid protests about alleged bias in general elections that were due to be held in late January.
The report did cautiously welcome legal amendments that made it easier for women to prosecute rape cases, but it said there was no decrease in violent crimes committed against women.