A panel of Iraqi judges detailed on Thursday 150 attacks they claimed were carried out by death squads under the command of Sunni Vice President Tareq al-Hashemi, in accusations likely to reignite political conflict.
The announcement is the latest episode in a stand-off between Shi'ite Prime Minister Nuri al-Maliki and Hashemi which has sparked a political crisis and prompted fears among Sunnis that Maliki is seeking more power at their expense.
Shortly after U.S. troops withdrew from Iraq in mid-December, Maliki sought Hashemi's arrest and the dismissal of a Sunni deputy prime minister. Sunni politicians held protests.
Abdul-Sattar al-Birqdar, spokesman for the Supreme Judicial Council, Iraq's highest court, listed 150 bombings and assassinations stretching as far back as 2005 that mainly targeted security forces and Shi'ites in Baghdad.
"This is only the beginning. The investigation is ongoing and the number of crimes could reach 500," one of the judges told reporters on the sidelines of a news conference in one of Baghdad's main court buildings.
The nine judges who make up the investigative committee are Sunni, Shi'ite, Turkmen and Kurdish. They refused to be named for security reasons, and some said they had received death threats. No cameras were allowed to film the judges.
Another judge said more than 70 people affiliated with Hashemi or his bodyguards had been detained. Nine others had been released for lack of evidence.
"Most of the activities of this group were in Baghdad. Until now, the investigation is focused on Baghdad," another judge said.
Hashemi was not immediately reachable for comment on Thursday but he has denied the allegations levied against him, calling the case a plot to destroy opponents of Maliki.
Iraqi authorities issued an arrest warrant for Hashemi on Dec. 19, a day after U.S. troops pulled out, triggering the row that has threatened to unravel a fragile power-sharing agreement between largely Shi'ite, Sunni and Kurdish blocs.
Lawmakers from Hashemi's Sunni-backed Iraqiya bloc responded to Maliki's moves by boycotting parliament, and its ministers walked out of the cabinet.
They have since returned to work, and a national conference is in the works to reconcile rival groups. But Thursday's announcement by the inquiry revived fears of renewed tensions.
Hashemi has left Baghdad for the semi-autonomous Kurdish north of the country, where he is unlikely to be arrested. He may, however, face more problems there as the inquiry also blamed him for the assassination of a Kurdish judge.
Birqdar said relatives of the victims would be able to bring charges against the accused.
Violence in Iraq has subsided since the sectarian civil war of 2006-2007, when Sunni insurgents and Shi'ite militia killed thousands of civilians each month after US invasion.