Iraqi and US authorities freed 495 prisoners from US facilities on Saturday, completing a mass release announced by the prime minister earlier this month as part of his national reconciliation efforts.
US Ambassador Zalmay Khalilzad welcomed the move and said more prisoners could be freed.
"We are prepared in consultation with the Iraqi leaders to make future prisoner releases and to take other concrete steps to facilitate reconciliation," he said in a statement. "As the government moves forward with these steps, it can count on support from the US government."
Prime Minister Al-Maliki had promised to release 2,500 inmates by the end of the month.