BAGHDAD, March 2 -- Nearly three years into a war epitomized by car bombs and suicide attacks, executions -- many of them following torture -- now account for up to three-fourths of the hundreds of corpses coming in to Baghdad's main morgue each week, the former U.N. human rights chief for Iraq said Thursday.

John Pace, who headed the U.N. human rights mission here until Feb. 13, said that between two-thirds and three-fourths of the victims brought to Baghdad's main morgue are recorded as casualties of gunshot wounds. Nearly all showed signs of having been executed, tortured or both, Pace said by telephone from his home in Sydney.

Pace said he held one of Iraq's factional militias principally responsible -- the Badr Organization, the armed faction of the Supreme Council for Islamic Revolution in Iraq, a Shiite Muslim religious party that is one of the most powerful members of Iraq's governing coalition.

"They have caused havoc," Pace said of the Badr group in a separate interview with the Associated Press. "They do basically as they please. They arrest people, they torture people, they execute people, they detain people, they negotiate ransom, and they do that with impunity."

Since the middle of last year, Shiite militias -- private armies that are sometimes closely integrated with the Shiite-dominated Interior Ministry -- have been accused of operating as death squads and of carrying out extrajudicial killings. The accusations have increased sharply over the past week, with the killing of hundreds of Sunni Arabs in retaliation for the Feb. 22 bombing of a Shiite shrine, the Golden Mosque in Samarra. Spokesmen for several factions have denied involvement in retaliatory killings.

An international official in Baghdad who is familiar with the tabulation of the death toll said Thursday that roughly 1,000 people were killed between the day of the bombing and Monday, when the government lifted a curfew imposed to stem the violence.

The international official, who spoke on condition he not be identified further, said the figure came from morgue officials and others before the government announced a much lower toll.

He said morgue officials and others acceded to the reduced official count because they feared the militias, the death squads and the government. "They're afraid," the official said.

Prime Minister Ibrahim al-Jafari said on Tuesday that 379 people had been killed since Feb. 22, and he described as inaccurate and exaggerated a Washington Post report that put the death toll at 1,300. The Post's tally was provided by a morgue worker, and an international human rights official who spoke on condition of anonymity said the source's job entailed close familiarity with the number of bodies the facility received.

The acting director of the morgue, Qais Hassan, also denied The Post's figure. "That's a lie," he said of the number on Thursday.

Hassan began running the morgue when the director, Faik Bakir, fled the country a few months ago after being threatened over the release of morgue information seen as linking many killings to death squads, officials said.

Another morgue official declined to comment, and the spokesman for the Health Ministry, which oversees the facility, did not answer his telephone Thursday. The Health portfolio is held by the party of the Shiite cleric and militia leader Moqtada al-Sadr.

The number of bodies processed by the Baghdad morgue has overtaken the toll from suicide and car bombings, most of which are blamed on Sunni Muslim insurgents. Morgue statistics are one way to measure cause of death in the cases of Iraqi victims of violence, because those killed by gunfire are taken to the city morgue, while victims of bombings are taken to hospital morgues because the cause of death is considered clear.

At the Baghdad morgue and in neighborhoods throughout the capital this week and last, families spoke of abductions by men wearing the black shirts and pants of the Mahdi Army, Sadr's militia.

In one Baghdad neighborhood Thursday, a widow draped in black said black-clad gunmen had burst into a mosque on Feb. 23 and abducted her husband and other men as they were finishing afternoon prayers. The captured men were subjected to a one-hour mock trial in a detention center near Sadr City, the heart of Baghdad's Shiite population and Sadr's base in the city, the widow said.

Some of the men were released, but her husband and three others were executed, she said. His family found his corpse in the Baghdad morgue on Saturday, shot in the face and chest, with his hands cuffed behind his back.

Fearful, the widow hesitated to say who she believed killed her husband. "Who is running the country?" she finally responded. "The Americans. The Mahdi Army. The Badr Brigade. They are responsible."

She hushed her daughters and granddaughter when they assigned blame more specifically. "Mahdi Army," her 8-year-old granddaughter whispered into her ear. "Darling," the widow said, frowning and quieting the girl.

Sadr officials have rejected responsibility for the killings. Sadr aides said other factions' militiamen were adopting black clothes to deflect blame onto the Mahdi Army.

The explosion of slayings and resulting accusations unleashed by the mosque bombing follow nearly a year of charges by Sunni leaders that Shiite fighters in militias and in the Interior Ministry were carrying out widespread killings of Sunni men. The bodies of hundreds of Sunnis have been found dumped in various places around Iraq, after the men were abducted from Sunni or mixed neighborhoods and communities.

After numbering in the dozens each month before the U.S. invasion and roughly 500 a month in the first half of 2005, bodies processed at Baghdad's morgue peaked at about 1,100 last July.

In November, 555 of the 886 bodies brought to the morgue bore gunshot wounds, as did 479 of the 787 brought to the morgue in December, according to the U.N. mission in Iraq, which tracks deaths reported by Baghdad's morgue.

The figures "are believed to underrepresent the actual number of casualties," the United Nations said in a report.

While violent crime has surged in Iraq in the upheaval following the U.S. overthrow of President Saddam Hussein, and while Sunni insurgents use guns as well as bombs, public suspicion with regard to the spike in execution-style deaths has centered on the Shiite militias and security forces.

Jafari's government has denied the existence of death squads within the Interior Ministry. U.S. Army Maj. Gen. Joseph Peterson said last month, however, that American troops in January arrested a group of Interior Ministry police commandos on the verge of executing a detained Sunni man.

The international human rights official said workers were under growing pressure to minimize anything seen as linking killings to death squads. Even before the past nine days' sectarian violence, the official said morgue officials were reluctant "to give even the most basic information on the number of victims."

"You can see that, over time, attitudes have changed," the official said, citing "a mix of pressure not to divulge and fear that there will be repercussions."

Militiamen and insurgents alike had threatened morgue workers against conducting autopsies or doing other investigations that would link the killers to their crimes, Pace said. "They are told it is not necessary and not in their interests,'' he said.

© 2006 The Washington Post Company