Iraqis on Thursday began picking up copies of the draft constitution that they will vote on next week, after the country's Shiite-led parliament ended a bitter dispute with Sunni legislators about how the referendum will be conducted.

Like other Iraqis, Lamia Dhyab picked up her copy at the small shop where she presents her ration card in south Baghdad (search) each month to get government-subsidized food for her family.

"We are going to read the draft constitution. If we like it, we will vote yes. If we don't, we'll say no," said Dhyab, who was wearing a chador, the traditional head-to-toe black outfit that Muslim females often wear.

Under U.S. and U.N. pressure, parliament on Wednesday reversed its last-minute electoral law changes, which would have ensured passage of the new constitution in the Oct. 15 referendum, but which the United Nations called unfair.

Sunni Arab leaders who had threatened a boycott because of the changes said they were satisfied with Wednesday's reversal and are now mobilizing to defeat the charter at the polls. But some warned they could still call a boycott to protest major U.S. offensives launched over the past week in western Iraq, the Sunni heartland.

On Wednesday, a bomb exploded at the entrance of a Shiite mosque in Hillah (search), a city south of Baghdad, killing at least 25 and wounding 93, as hundreds of worshippers gathered there for prayers at the start of the Islamic month of Ramadan (search) and for the funeral of a man killed two days ago in a bomb blast at his restaurant.

It was the latest in a string of insurgent attacks — targeting Shiite Muslims in particular — aimed at wrecking the referendum. Al Qaeda in Iraq (search), which has declared "all-out war" on Shiites, has called for stepped-up violence during Ramadan, the Muslim holy month now under way.

On Thursday, attacks by insurgents continued. A suicide car bomb exploded near a U.S. military convoy in Karada (search), an eastern area of Baghdad, killing one Iraqi bystander and wounding four others, police said. No American casualties were immediately reported.

At least 271 people have been killed by insurgents in Iraq in the past 11 days.

Thousands of U.S. and Iraqi troops were waging two major offensives in western Iraq, the Sunni heartland, in an attempt to put down insurgents ahead of the vote.

At least 42 insurgents have been killed in the Iron Fist (search) offensive, which began Saturday near the Syrian border, and at least four U.S. servicemen have died in Iron Fist and River Gate, the offensive that began further to the east Saturday, the U.S. military said.

In all, at least 1,943 U.S. service members have died since the beginning of the Iraq war in March 2003, according to an Associated Press count.

On Sunday, the Shiite-led parliament issued a new interpretation of the rules for the constitutional referendum, saying two-thirds of registered voters had to vote "no" — not two-thirds of those casting ballots. That raised the bar for rejection, and outraged Sunnis threatened a boycott.

The United Nations (search) called the change unfair, and U.N. and U.S. officials pressed the government to reinstate the original rules. On Wednesday parliament did so.

Iraq's Shiite majority and the Kurdish minority overwhelmingly support the constitution. Sunni Arabs make up only 20 percent of the population but can still defeat the constitution if they get a two-thirds "no" vote in any three of Iraq's 18 provinces. There are four provinces where they have a chance of doing so.

Many Sunnis fear the constitution would divide the country into three districts: a Kurdish one in the north and a Shiite one in the south that both control Iraq's oil wealth, and a poor majority Sunni one in central and western areas.

Wednesday's parliament vote was a political victory for U.N. and U.S. officials, boosting chances that Sunnis will see the referendum as fair and participate, thus giving the outcome credibility.

Yet that success restored the possibility that Sunnis will manage to veto the constitution, which would prolong Iraq's political instability. The United States in particular is eager to see the passage of the charter, seen as key to beginning the withdrawal of some U.S. forces.

Saleh al-Mutlaq, a top Sunni politician, said the boycott threat over the election law was lifted. "With this result, the Sunni Arabs will be able to defeat the constitution," he told The Associated Press on Wednesday. "I am sure if there is honesty (in the election process) 95 percent of the Sunni Arabs will vote 'no."'

But he warned that Sunnis might still call a boycott if the U.S. offensives do not end soon, saying the turmoil will suppress Sunni voting.