Baghdad, Iraq ? Iraqi officials said Saturday they were considering new measures to protect voters in the Jan. 30 national election, including a three-day nationwide ban on driving to discourage car bombings. Fresh clashes broke out in the troubled northern city of Mosul, where most election officials have fled their jobs in fear.

A U.S. military helicopter made an emergency landing in Mosul after drawing ground fire, the U.S. command said. And a U.S. Marine was killed in action Saturday in a tense area just south of Baghdad.

U.S. and Iraqi officials fear a surge in insurgent attacks as the election approaches. Many members of the Sunni Arab minority are expected to boycott the balloting, and Sunni rebel groups have threatened to attack polling stations.

To prevent that, an Iraqi Cabinet minister said authorities were considering a number of special measures, including restrictions on the movement of private vehicles, and possible security cordons around polling stations.

Provincial Affairs minister Waeil Abdel-Latif gave no details about the proposed restrictions, but security officials said they included banning all private vehicles for three days around the election. That would make it easier to spot would-be vehicle bombers and to inhibit rebel movements.

“The government is determined to make available facilities and security guarantees to ensure the success of the election,” Abdel-Latif said.

Underscoring the security threat, fresh clashes broke out Saturday in Mosul between U.S. troops and insurgents after the rebels blasted an American convoy.

After the blast, insurgents opened fire on American troops, who then raided a nearby agricultural research station looking for the assailants.

In Baghdad, Brig. Gen. Carter Ham, the U.S. general responsible for security in northern Iraq, said virtually every election worker in Ninevah province, which includes Mosul, quit recently because of security fears.