Insurgents attacked three polling stations in Baghdad during Iraq's constitutional referendum on Saturday, wounding two policemen and a civilian, police said. Violence also occurred in Ramadi, a city west of Baghdad, and near the southern city of Basra, but no injuries were reported. In the first attack in Iraq's capital, a roadside bomb exploded near a polling station in the western area of Amiriyah as it opened at 7 a.m., wounding two policemen, said police Lt. Mohammed Kheyon. No voters were there yet, he said. At 8:30 a.m., a small rocket exploded near a polling station in Azamiyah, northern Baghdad, slightly wounding one civilian, said police Lt. Thaer Mahmoud. Elsewhere, in the nearby area of Kazemiyah, a mortar round fell near a polling station at 9 a.m., but it did not explode, said police Maj. Falah al-Mhamadawi. In Ramadi, 115 kilometers west of Baghdad, fighting erupted at about 7 a.m. between a small group of insurgents and US troops patrolling the mostly empty streets of the city, said police 1st. Lt. Mohammed Al-Obaidi. No injuries were immediately reported. South of Basra, three armed men attacked an empty polling station at 3 a.m. and were caught and arrested, said police Capt. Mushtaq Kadim. Sunni-led insurgents had vowed to wreck Saturday's referendum at about 6,000 polling stations across Iraq. In the 19 days before the voting, nearly 450 people were killed by insurgents using suicide car bombs, roadside bombs and drive-by shootings. Iraqis went to the polls Saturday morning to give a "yes" or "no" to a new constitution aimed at defining democracy in a nation once ruled by Saddam Hussein and now sharply divided among its Shiite, Sunni and Kurdish communities. As the polls opened at 7 a.m., the capital was eerily quiet under clear blue skies. Iraqi soldiers and police ringed polling stations at schools, and driving was banned to stop suicide car bombings by Sunni-led insurgents determined to wreck the vote. Only a few citizens were seen walking to the schools, which were protected by concrete barriers and barbed wire. But President Jalal Talabani and Prime Minister Ibrahim al-Jafaari were shown live on Al-Iraqiya television voting in a hall in Baghdad's heavily fortified Green Zone, where parliament and the US Embassy are based. After putting their paper ballots in white-and-black plastic boxes, both smiled and waved to the public. "I announce the beginning of the first referendum process in the history of new Iraq, and it is being conducted all over the country in about 6,000 polling stations," Farid Ayar, a top official in the Iraqi Independent Electoral Commission, said in an interview. Insurgents had sabotaged power lines Friday night, plunging the Iraqi capital and other nearby regions into darkness, but government employees working through the night managed to restore electricity in Baghdad before dawn. The choice of target may suggest that security measures hampered militants from carrying out the sort of devastating bombings against civilians or police that they have unleashed before the vote. Nearly 450 people were killed in the 19 days before the referendum, often by insurgents using suicide car bombs, roadside bombs and drive-by shootings. Iraqis remain deeply divided over the approximately 140-charter draft constitution they were voting on Saturday. The country's Shiite majority - some 60 percent of its 27 million people - and the Kurds - another 20 percent - support the charter, which provides them with autonomy in the regions where they are concentrated in the north and south. Shiite spiritual leader Grand Ayatollah Ali al-Sistani called on followers to go to the polls and back the constitution. A similar call during January parliamentary elections rallied millions of Shiites to vote. However, the Sunni Arab minority, which dominated the country under Saddam and forms the backbone of the insurgency, widely opposes the draft, convinced its federalist system will eventually tear the country apart into Shiite and Kurdish mini-states in the south and north, leaving Sunnis in an impoverished center. Many of them feel the document doesn't sufficiently support Iraq's Arab character. Last-minute amendments in the constitution, adopted Wednesday, promise Sunnis the chance to try to change the charter more deeply later, prompting one Sunni Arab group - the Iraqi Islamic Party - to support the draft Saturday. Most others still reject it, but a split in the Sunni vote may be enough to ensure its passage. The United States hopes that the constitution's success will pave the way for withdrawing American troops. In Friday sermons across the nation, the message from Shiite pulpits was an unequivocal "yes," but it was not so clear-cut in Sunni Arab mosques - varying from "yes," "no" and "vote your conscience." In Tikrit, Saddam's hometown north of Baghdad, Sheik Rasheed Yousif al-Khishman exhorted worshippers at the al-Raheem mosque to reject the charter, saying the draft was an "infidel constitution written by foreign hands." In the nearby town of Samarra - another bastion of Sunni militancy - Sheik Adil Mahmoud of the influential Sunni Association of Muslims Scholars delivered a more tempered sermon. "I will go to the polls and vote 'no,' but I leave the choice to you," he said. The bitterness, however, was clear. Hundreds of Sunnis marched after prayers on Baghdad's Abu Hanifa mosque - seen as a stronghold of the Iraqi Islamic Party - and denounced the party as traitors for backing the draft. Insurgents launched five attacks against the party on the eve of the referendum, bombing and burning offices and the home of one of its leaders in cities such as Baghdad and Fallujah, west of the capital. Nobody was injured in the attacks. For most of the day Friday, Iraqis were hunkered down in their homes, with the streets of the Iraqi capital almost empty hours before a 10 p.m. curfew and the country sealed off from the outside world as borders and airports were closed. Tens of thousands of Iraqi army troops and policemen, meanwhile, formed security rings around the nation's estimated 6,000 polling stations and set up checkpoints on highways and inside cities. "Besides Allah, we need this constitution to protect us," said Rajha Abdul-Jabar, a 49-year-old Sunni Arab mother of five married to a Kurdish dentist. "I, my husband and our children will go and vote 'yes' tomorrow," she said in the small convenience store she runs. Jameel Safar, a 30-year-old Kurd in Baghdad, said the charter will safeguard Iraq's unity, but later added: "The Kurds are entitled to everything. We have a right to our own nation like everyone else." Ratification of the constitution requires approval by a majority of voters nationwide. However, if two-thirds of voters in any three of Iraq's 18 provinces vote "no," the constitution will be defeated and Sunni Arab opponents have a chance of swinging the ballot in four volatile provinces - Anbar, Nineveh, Salahuddin and Diyala.