TIKRIT, Iraq - Politicians in Saddam Hussein's hometown urged Sunni Arabs to vote "no" in next week's constitutional referendum and insurgents killed one Iraqi and injured 10 with roadside bombs and drive-by shootings on Saturday.

On Friday, six Marines were killed by bombs as the U.S. military announced it had completed a major sweep in western Iraq aimed at suppressing al-Qaida militants before the constitutional vote.

The military said 50 insurgents were killed in the six-day Iron Fist offensive, launched Oct. 1 in towns near the Syrian border. The operation, which ended on Thursday, was the first in a series of major offensives in the past week in the heartland of the Sunni-led insurgency.

U.S. forces have swept through the area before - most recently in May. But militants have always returned, bringing in foreigners from Syria and planning attacks in other parts of the country. The military said they now plan to maintain a long-term presence there.

The military has said it will wrap up the operations in time for Sunni Arabs in the region to vote in the Oct. 15 referendum.

But two other U.S. and Iraqi offensives - River Gate and Mountaineers - were still under way in Anbar province, a Sunni-led insurgency stronghold where Operation Iron Fist was also conducted. The area stretches along the Euphrates River valley, which runs from the Syrian border to the city of Ramadi, about 70 miles west of Baghdad.

A third offensive, Operation Saratoga, recently began in northern Iraq to improve safety in towns such as Kirkuk and Sulaimaniyah.

Seven days before Iraqis were to approve or reject the draft constitution, most were still waiting for copies of it to read. Distribution began in a few Baghdad neighborhoods, but did not appear to have spread to many other areas.

If two-thirds of the voters in any three of Iraq's 18 provinces vote "no," the referendum fails and Iraq's parliament must be dissolved and replaced in another election. Four of the country's provinces have Sunni majorities.

Last month, the Iraqi Islamic Party, country's largest Sunni political organization, urged Iraqis to reject the constitution, saying it threatened "national unity and the identity of Iraqi people."

That "no" campaign came to Saddam's hometown of Tikrit on Friday night when the local division of the party distributed about 150 copies of the constitution after prayers at the Tikrit Mosque and urged the worshippers to reject it.