The detainees were the first of 2,000 prisoners whom al-Maliki promised would be freed from Iraq's most notorious prisons in an apparent effort to ease anger among minority Sunnis over allegations of arbitrary detentions and mistreatment of prisoners.
Italy's center-left government was also making good on a pledge: Foreign Minister Massimo D'Alema was in Baghdad Wednesday to discuss plans for a complete pullout of Italian troops from Iraq by the end of the year.
In other developments:
Al-Maliki, a Shiite who took office two weeks ago, has made security and reconciliation among Sunnis and Shiites a priority of his government. He has stressed, however that the detainee release plan excludes loyalists of ousted leader Saddam Hussein and his Sunni-dominated Baath Party, as well as "terrorists whose hands are stained with the blood of the Iraqi people."
The government said 2,000 detainees whose cases have been reviewed will be released in the coming days in batches of about 500. The first 594 were released Wednesday from U.S.- and Iraqi-run prisons around Iraq, including Abu Ghraib.
Al-Maliki had said Tuesday that 2,500 would be released, but changed that number to 2,000 Wednesday.
Iraqi officials have said there is an agreement to release up to 14,000 detainees once their cases have been reviewed. A U.N. report last month said there were 28,700 detainees in Iraq.
Omar al-Jubori, a member of the Iraq Islamic Party, the largest Sunni Arab group in the governing coalition, said the agreement came after negotiations with U.S. Embassy and military officials and street demonstrations. He said the releases would "give happiness and hope to every detainee and every oppressed person in this country."
D'Alema's visit to the Iraqi capital comes two days after an Italian soldier was killed in an attack on a military convoy, reports CBS News correspondent Sabina Castelfranco. Italy's military contingent of 2700 troops, the fourth-largest contingent, is based in the southern Iraqi city of Nasiriyah, about 200 miles southeast of Baghdad. D'Alema said some Italian troops would be withdrawn this month.
The announcement falls in line with a previous pullout plan by former Italian Premier Silvio Berlusconi, but it is the first time that a timetable has been given.
"We have a voters' mandate: the troops are coming back home," D'Alema said.
Italy follows Spain, Bulgaria and other staunch U.S. allies to either pull out or reduce troops that are part of the Multinational Forces in Iraq. About 150,000 foreign troops are in Iraq — with 130,000 belonging to the United States.
Al-Maliki has announced he wants to take over security from U.S.-led forces within 18 months, starting with four southern provinces by the end of the year. The plan would put American and international forces in a supervisory role, part of an exit strategy that will eventually allow the troops to go home.
Although Iraq may take over security control, it remains doubtful at this point if al-Maliki's much-touted national unity government will be able to restore order to Baghdad, let alone Iraq as a whole.
Militias are believed to have infiltrated police forces and have killed hundreds in sectarian violence, personal vendettas and kidnappings for ransom.
Al-Maliki has blamed a desire by insurgents to cripple the political process for the spike in violence since he took office just over two weeks ago.
Al-Maliki has stressed that the release plan excludes loyalists of ousted leader Saddam Hussein and his Sunni-dominated Baath Party as well as "terrorists whose hands are stained with the blood of the Iraqi people."
"All the prisoners in the American and the governmental prisons will be released, to give happiness and hope to every detainee and every oppressed person in this country," said Omar al-Jubori, a member of Iraqi Islamic Party — the largest Sunni Arab grouping the coalition government.
He said negotiations with U.S. embassy and military officials, along with demonstrations and protests, had allowed the government to "reach an agreement to release 14,000 detainee from the American prisons."