Lawmaker Hakim al-Zamili, who sits on parliament's security and defense committee and is affiliated with anti-American cleric Muqtada al-Sadr's political bloc, said al-Maliki expects to negotiate a new deal with Russia that would seek additional equipment and new prices.
"There was clear corruption," he said.
Iraq's acting defense minister, Saadoun al-Dulaimi, echoed the suggestion that the government plans to renegotiate the deal, seeking better terms.
At a news conference in Baghdad, he insisted no money has changed hands so far, and said the existing proposal "has become meaningless."
Russia and the Soviet Union were key suppliers of weapons to Saddam Hussein, the late Iraqi dictator who was ousted during the 2003 U.S.-led invasion.
The United States is now the largest supplier of arms to Iraq, which has agreed to buy a range of American-made weapons, including tanks and F-16 fighter jets.
A small number of U.S. military personnel remained in Iraq after last year's troop withdrawal as an arm of the American embassy. They are responsible for facilitating Iraqi arms purchases and training the Iraqis how to use and maintain the weapons.
Associated Press writers Bushra Juhi in Baghdad and Mansur Mirovalev in Moscow contributed reporting.
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