Clinton told reporters at the State Department Monday that U.S. officials are involved in trying to help Iraqi politicians sort out their differences over an elections law that must pass before the vote can be held.
The election is supposed to be conducted in January. Clinton mentioned no specific dates but said the election "might slip" as a result of the continuing dispute over the elections law. She expressed confidence that the voting eventually will be held.
Iraq's parliament amended the country's vetoed election law on Monday with a version that failed to appease Sunni Arabs, who fear they are being marginalized.
The dispute highlights the ethnic and sectarian divisions in Iraq. While more secure than in past years of war, the country has yet to achieve the political reconciliation vital to long-term stability.
Vice President Tariq al-Hashemi, a Sunni, vetoed the law because he wanted more seats for Iraqis living abroad, most of whom are Sunnis. The minority, dominant under Saddam Hussein, has seen its privileged status evaporate since the ouster of the dictator and the election of a government led by the Shiite majority.
After days of intense negotiations by political blocs, lawmakers voted to change the basis for distributing seats, most likely giving more seats to the powerful Kurdish bloc rather than to the Sunnis.
The number of seats in parliament will be expanded from 275 to around 320 under the amended law to reflect population growth.
The pre-vote dealmaking appeared to focus mostly on efforts to address complaints about the electoral system from the Kurds in order to win their support for the law, causing dozens of Sunni lawmakers to walk out.
"What has happened today represents a setback to the policy of political accordance that the parliament has adopted," said Salim Abdullah, spokesman for the Accordance Front, the biggest Sunni bloc in the parliament.
Al-Hashemi is likely to veto the amended law now that it returns to the three-member presidential council, but parliament can override a second veto with a three-fifths majority. Shiite and Kurdish political blocs have enough votes for an override.
"We will wait for the answer from the presidential council before deciding future moves," said Faraj al-Haidari, chief of the election commission. "I think that it is very difficult to hold the elections in January. Most probably, it might be moved to February."