Iraq in Lockdown on Eve of Provincial Vote
Other planned security measures included closing the southern city of Basra and ordering traffic bans across Baghdad. Hundreds of women, including teachers and civic workers, have been recruited to help search women voters after a rise in female suicide bombers last year.
More than 14,400 candidates are competing for 440 seats in 14 of the country's 18 provinces.
The polls open Saturday across Iraq at 7 a.m. (0400 GMT, 11 p.m. Friday EST) and close at 5 p.m. Saturday (1400 GMT, 9 a.m. EST). Results are not expected for several days.
Boundaries of the northern city of Mosul were closed Friday morning to vehicles and a citywide curfew was scheduled to take effect several hours later, said Police officer Col. Safaa Abdul-Razzaq, spokesman for the joint operations command in the Ninevah province. Residents were barred from leaving their homes until they go to cast their ballot.
Abdul-Razzaq said the curfew was imposed to curb any potential violence during voting in Iraq's third largest city. The vehicle ban is in place in Mosul until Sunday.
Iraq also sealed its border crossings with Iran, and the southern city of Basra was to be sealed from Friday night until Sunday morning, said Iraqi Interior Ministry spokesman Maj. Gen. Abdul-Karim Khalaf.
"The air and land borders will be sealed, but there will be no restriction on people's movements within the city," Khalaf said.
Most other cities are expected to take the same measures by late Friday.
While Baghdad and other cities in Iraq have enjoyed substantial security gains, Iraq and U.S. forces continue to battle al-Qaida and other insurgents in Mosul.
The multiethnic city has been one of the hardest to tame after insurgents fled to the area following U.S.-Iraq security crackdowns elsewhere.
Tensions rose there ahead of the elections as Kurdish and mainly Sunni parties jockeyed for power.
The U.S. military is taking a sideline role in direct security for the elections, but plan to send heavy troop deployments into the streets during the voting.
The city closures came a day after attacks left three candidates dead across Iraq, including a candidate in Mosul who was killed by gunmen firing from a passing car. The candidate and former army officer, Hazim Salim, was a member of the Unity List, a group of independent Sunni politicians, according to an Iraqi police official who spoke on condition of anonymity because he was not authorized to release the information.
The head of the United Nations office in Baghdad, Staffan de Mistura, condemned the killings as "a terrible crime designed to attempt to disrupt the democratic process." He expressed confidence that Iraqis would be "undeterred by isolated intimidating tactics" and show up at the polls.
A roadside bomb found south of Baghdad on Friday killed three officers and wounded 17 others after it exploded while they were trying to diffuse it, another Iraqi police official said.
The bomb exploded inside a police compound in Diwaniyah where it was taken to be diffused by an explosive ordnance disposal team, said the official, who also spoke on condition of anonymity because he was not authorized to release the information.
Associated Press reporter Qassim Abdul-Zahra in Basra contributed to this report.