BAGHDAD — Iraq's parliament passed on Sunday a long-delayed law in a crucial step to setting up nationwide elections, and the head of the electoral commission said he did not expect any major delays in the vote planned for January.

The decision appeared to resolve a key sticking point -- who will be allowed to vote in the disputed, oil-rich city of Kirkuk. U.S. Ambassador Christopher Hill could be seen shuttling between various political factions in the hours leading up to the passage of the law, in an indication of Washington's concern that a delay in the election could hold up the American troop withdrawal from Iraq.

President Barack Obama, speaking at the White House, welcomed the new legislation.

"This is an important milestone as the Iraqi people continue to take responsibility for their future. I want to congratulate Iraq's leaders for reaching this agreement," Obama said. "The United States will continue to stand with Iraq as a strong partner and as a friend."

The elections were originally planned for Jan. 16 and the head of the independent High Electoral Commission, Faraj al-Haidari, said he expected a vote within a week of that date.

"The date will be after Jan. 16, and I think it will be within one week after Jan. 16," he told The Associated Press after the law was passed. The Iraqi constitution mandates that the vote takes place in January, but does not specify which day.

Once the legislation is approved by the president and his two vice-presidents, the election commission will decide how many days are needed to hold the vote. Then the commission will send a letter to parliament and to the prime minister to inform them of their decision.

The law's passage had been repeatedly delayed by sharp disagreements over how voting would take place in the northern city of Kirkuk, claimed by both Arabs and Kurds and a major flashpoint in the country.

Kurds consider Kirkuk a Kurdish city and want it part of their self-ruled region. During the rule of former dictator Saddam Hussein, tens of thousands of Kurds were displaced under a forced plan by Saddam to make Kirkuk predominantly Arab. The Arab-led central government vehemently opposes anything that would remove Kirkuk from its control.

Although there were few details immediately available on how the Kirkuk issue was decided, both Kurds and Arabs appeared to claim victory after the sometimes raucous parliament session ended.

The law passed with 141 votes, but it was not immediately known how many of the parliament's 275 members voted against the legislation or even attended the session. Low turnouts are common in Iraq's parliament, which often do not have enough people to form the necessary 138-person quorum.