Iraqi Prime Minister Nouri al-Maliki says he hopes lawmakers can reach a final decision on a possible extension of the U.S. military presence in the country at a meeting on Tuesday.

He made the comments in a statement posted on his website late Monday ahead of a meeting of the country's political blocs at President Jalal Talibani's residence.

U.S. forces are scheduled to withdraw from Iraq at the end of the year, but both U.S. and Iraqi officials have expressed concern about Baghdad's ability to cope with security after the withdrawal.

The United States has grown increasingly frustrated with the lack of a decision from Iraq on whether it will seek an extension.

Joint Chiefs of Staff head Admiral Mike Mullen said Tuesday that he understands there are difficult political challenges associated with a potential deal, but repeated that Iraqi leaders need to decide “as soon as possible.”

Mullen told reporters there will come a time when it is too late to reverse a planned withdrawal, and all of the U.S. troops will have to leave.

He also said any agreement to keep American troops in Iraq beyond the deadline must include guarantees of legal immunity for U.S. forces.

The joint chiefs chairman commented after a meeting with Mr. Maliki in Baghdad. He also accused neighboring Iran of interfering in Iraq. He said Tehran had been arming militants who carried out attacks on Iraqi soil.