A key amendment sought by the United Iraqi Alliance would be a more firmly set a date all U.S. troops to leave Iraq in 2011, The Washington Post reported.

As written, the draft language would require U.S. forces to leave by December 2011 but provides for an extension by mutual agreement.

The Shiite bloc, which includes Iraqi Prime Minister Nouri al-Maliki's Dawa party, also demanded a larger role for Iraqi officials in determining whether U.S. soldiers accused of wrongdoing are subject to prosecution in Iraqi courts, said Sami al-Askeri, a lawmaker and Maliki political adviser.

If the alliance's conditions aren't met, "I cannot see that this agreement will see the light," Askeri said, adding whether the agreement would be signed "will depend on the American side."

A White House official declined to comment, The New York Times reported.

The draft status-of-forces document would provide legal authority for U.S. troops to remain in Iraq after a U.N. mandate expires Dec. 31.