North Carolina-based Blackwater is the largest contractor providing security in Iraq. Most of its work for the State Department is in protecting U.S. diplomats in Iraq. The company has not been charged in connection with the shooting.

The five guards, all dressed in dark suits and ties, said nothing while in the courtroom.

A sixth, however, is cooperating with the government. Jeremy Ridgeway of California pleaded guilty to one count each of manslaughter, attempted manslaughter, and aiding and abetting. In his plea agreement with prosecutors, Ridgeway admitted there was no threat from a white Kia sedan whose driver, a medical student, was killed and his mother, in the front passenger seat, was injured.

Urbina ordered prosecutors to give defense lawyers copies of Ridgeway's sealed plea agreement in three months.

In a separate case, another former Blackwater security contractor will soon be charged in the killing of an Iraqi guard in 2006, his lawyer said.

Andrew Moonen of Seattle, a former Army Ranger, fatally shot a 32-year-old guard for Iraqi Vice President Adil Abd-al-Mahdi while wandering around drunk after a Christmas Eve party in 2006, according to a congressional report.

Moonen, now 28, said he had been in a gunfight with Iraqis. Blackwater arranged to have the State Department fly him back to the United States, fired him and fined him, and paid the slain guard's family $15,000.