Iraq's deeply divided Shiites, Sunnis and Kurds voted in large numbers on a new constitution Saturday — a referendum mostly free of insurgent violence and aimed at establishing democracy after decades of Saddam Hussein's repressive rule.

In the south, Shiite women in head-to-toe veils and men emerged from the poll stations flashing victory signs with fingers stained with violet ink, apparently responding in mass to the call by their top cleric to support the charter.

But in Sunni regions — both in Baghdad (search) and several key heavily Sunni provinces — the surprisingly high turnout seemed to consist largely of Iraqis voting "no" because of fears the charter would set in stone the Shiite domination they fear.

"The constitution is a sign of civilization," Prime Minister Ibrahim al-Jaafari said after casting his ballot. "This constitution has come after heavy sacrifices. It is a new birth."

Overall turnout was about 61 percent and surpassed 66 percent in seven of Iraq's 18 provinces, including key Sunni Arab-majority ones, according to initial estimates, election officials said Saturday.

Some 250 election workers in Baghdad were starting to compile the ballots, collecting the summarized results and ballot boxes from around the country to count. So far, only materials from areas close to the capital have arrived, and no results were expected Saturday night, said Farid Ayar of the Independent Elections Commissions of Iraq (search).

"Initial estimates are that the turnout is no less than 61 percent," said Abdul-Hussein Hindawi, another senior IECI member said.

More than 66 percent of voters cast ballots in the three crucial provinces that could decide the vote — Salahuddin, Diyala and Ninevah, each of which has a Sunni majority but also significant Shiite or Kurdish populations, Ayar said.

Sunni opponents are hoping to get a two-thirds majority "no" vote in these provinces, which would defeat the constitution. Sunnis appeared to have turned out in surprisingly large numbers Saturday, many of them saying they were voting to reject, suggesting the final results could be close.

Other provinces with a similar rate of participation were Baghdad and Tamim — with mixed Sunni, Kurdish and Shiite populations — and the overwhelmingly Shiite provinces of Babil and Karbala, in the south.

Most provinces in the mostly Shiite south and the three provinces that make up the autonomous area of Kurdistan in the north had turnout rates between 33 and 66 percent, Ayar told a Baghdad press conference soon after polls closed Saturday evening.

Fewer than 33 percent of voters cast ballots in the southern Shiite province of Qadissiyah (search), he said. He did not give specific figures for any province.

The figures suggested a somewhat higher enthusiasm for voting in the mixed provinces than in the heartlands of Iraq's Shiite majority and Kurdish minority, where approval of the constitution was all but assured.

There was no information on turnout in Anbar, the vast western province that is overwhelmingly Sunni Arab and is the main battlefield between U.S.-Iraqi forces and the insurgents, Ayar said.

Anbar's largest city, Fallujah, saw thousands voting on Saturday. But in other towns and cities, where fear of insurgent retaliation was higher, almost no one was seen going to the polls.