An Iraqi electoral employee waited Saturday to empty ballot boxes for counting at a polling site for Iraqis in Damascus, Syria.

BAGHDAD -- Few doubted that the choice of the country's next prime minister would prove to be one of the most intractable disputes in forging a new government to lead Iraq as the American military withdraws.

But in negotiations that could last months, the presidency, a largely ceremonial post, has emerged as a growing quarrel, threatening to upset Iraq's still tenuous and ambiguous arrangements of sect, ethnicity and power.

It was the latest demarcation across a political map that grew more muddied on Saturday as early returns from last week's election showed Prime Minister Nuri Kamal al-Maliki's coalition, whose seats compose the single biggest bloc in Parliament, taking the lead in Baghdad. But his rivals appeared to perform respectably in the capital and in Nineveh and other provinces with a Sunni Arab majority and in rural Shiite Arab regions of southern Iraq.