"The government can't just sew together an outfit and dress the people up by force. We do not see ourselves or see our future in this draft. The Shia and Kurdish authorities who drafted it are promoting their own interests, not those of all Iraqis," said Gazwan Abd al-Sattar, 27, a Sunni Arab teacher voting in the northern city of Mosul.
"I followed the advice of Grand Ayat Allah Ali Al-Sistani, our great cleric. He said to vote yes and he knows what is best for us," said Jalal Fuad, 35, a self-employed Shia, who voted yes in Baghdad, even though he had not read the draft constitution.
"The constitution is a sign of civilisation. We consider this a day of great achievement. This constitution has come after heavy sacrifices. It is a new birth," said Prime Minister Ibrahim al-Jaafari, after casting one of the first ballots in Baghdad after Iraq's polls opened at 7am (0300 GMT).
"I hope they have a really big turnout. The closer they get to independence, the closer we get to going home," US marine Lance Corporal Sam Smithson of Sacramento, California, said as he helped guard the entrance of a polling station in the city of Haditha, where few cast ballots.
"This voting is for my future, the future of my children, my family and the rest of the Iraqi people. It is a new law and a new constitution and I have voted yes for it," said Jalal Keo, an Iraqi National Guard soldier who voted in the southern city of Basra.
"The UN is here to help the Iraqi people, to help them determine their future, and we have facilitated the work of the Iraqi Independent Electoral Commission," said Carina Perelli, director of the Electoral Assistance Division of the United Nations, speaking in Baghdad.
"Sunni Arabs closed themselves out of the political process by boycotting January's election. That was a big mistake. We must all go to the polls and vote today against a constitution that would cancel out this country's Arab identity," said Harith Abd al-Karim, 46, a Sunni who voted no in Falluja.