About 450 detainees walked free Tuesday from the U.S.-run Abu Ghraib prison west of Baghdad and other detention centers across the country.
Mr. Maliki has promised to release 2500 prisoners by the end of the month. Officials say those being freed were not involved in violent crimes, or they had been detained by mistake.
Meanwhile, the U.S. military says separate insurgent attacks killed an American Marine and a soldier outside Baghdad, Tuesday. And a car bomb in Kirkuk killed three Iraqis.
In another development, Iraq's High Tribunal says the second trial of Saddam Hussein and several of his former top officials will start on August 21. They are charged with genocide and accused of killing tens of thousands of Kurds in the 1980's Anfal campaign.
The campaign to crush a Kurdish uprising also included the gassing in Halabja in 1988 that killed 5,000 people.
Saddam and seven co-defendants are currently on trial on charges they murdered 148 Shi'ites from the village of Dujail. The deaths followed an assassination attempt against the former Iraqi dictator in 1982.