Iraqis in the Sunni-dominated Salahudin province will possibly say "No" in Saturday's referendum, some residents told Xinhua on Friday.
"We insist on participating in the referendum to veto the draft, " said Umer Hammash, a resident in the provincial town of Dhuluiyah.
"We will be human shields for the voting centers tonight, and we will go there after sunset to stay and protect the centers from whoever want to prevent the Sunnis from defeating the draft," he continued.
Salahudin is one of the three main Sunni Arab provinces which are expected to veto the constitution if most of the more than 500, 000 constituents said "No" to the draft.
On the eve of the referendum, streets in the main cities of the province were blocked by barricades for Saturday's curfew.
"The security operation would be 100 percent Iraqi, and we had experience from the past elections this year," Brigadier Issa Abd Muhmoud, head of the US-Iraqi Joint Coordination Center in Tikrit, told Xinhua.
Deputy Governor of Salahudin Abdullah Hussein Jebara was keen to say "No."
"It is the beginning to divide Iraq and waste its wealth," he argued.
Jebara said some 249 voting centers have received their ballot boxes across the province. Moreover, there are mobile voting centers touring in the remote areas in the province where it would be difficult for residents to vote.
Residents of the mainly Sunni province were furious on Friday after the Iraqi Islamic Party, a leading Sunni party, called on Sunni Arabs to vote "Yes."
"The leadership of the party behaved against the Iraqi interest which disappointed many of the party's members," said Abdullah Abdul Rahman, a member of the party.
Although facing pressure from Sunni Iraqis against the charter, Salahudin Governor Hamad Hemood al-Qaissi still showed optimism.
"The province is ready for the referendum and I call on our people to actively participate," Qaissi told Xinhua.
"I support every word of the draft constitution," Qaissi affirmed.
Sunni Arabs account for 80 percent of the population of the province, plus the Turkman minority whose political leader in Tuz Khurmato said his people would reject the draft.
Over 6,000 polling sites around Iraq will open from 7 a.m. ( 0400 GMT) to 5 p.m. (1400 GMT) on Saturday for about 15.5 million eligible voters out of Iraq's total estimated population of 26 million.
According to the timetable of Iraq's political process, new elections will be held by the end of this year to form a new parliament if the charter is approved by Iraqi voters in Saturday's referendum.
However, if two thirds of the voters in any three of the 18 Iraqi provinces say no in the referendum, the constitution will be vetoed, and then the parliament will be dissolved.