RAMADI, Iraq — Security concerns, roadside bombs and a series of brief gunbattles kept most Ramadi citizens from participating in Sunday’s historic Iraqi elections.

One U.S. soldier was killed and at least two others injured by a roadside bomb around 3 a.m. Sunday, according to military officials. In another attack at noon, a Humvee patrolling less than 200 meters from a polling station was hit by another bomb, sending a huge plume of smoke into the sky.

The Humvee crew all escaped with minor wounds, but the explosion touched off long bursts of machine-gun fire from Iraqi and American troops manning security positions at the nearby polling site, a large grammar school compound.

According to soldiers who were observing from a nearby rooftop position, the second roadside bomb was planted by a teenage boy who ran into the street and dropped a large plastic bag just moments before a U.S. patrol drove through.

For long minutes after the explosion, ammunition from the Humvee continued to cook off and fire into the air.

Before the explosion, 75 people — including Independent Electoral Commission of Iraq poll workers and special police commandos protecting the site — had voted at the school in eastern Ramadi, U.S. military officials said. At midmorning, the nearby streets had been full of curious residents watching voters walk to the polling station. After the explosion and gunfire, the streets were deserted and no other voters came.

Ramadi’s 400,000 residents were subject of a harassment campaign by insurgents, who promised death to anyone who voted Sunday.

At another polling site in the Sofiya district of Ramadi, the polls were more active. More than 100 people had voted by early afternoon, officials said. There were eight polling stations in the city of Ramadi, U.S. and Iraqi officials said, and they estimated that about 1,000 people cast ballots during the day.

“I’ll never forget this day,” said Pfc. Branden Bell, a 19-year-old infantryman from Napa, Calif., who had been manning the polling entrance closest to the second Humvee explosion.

Bell and another soldier with Company C, 1st Battalion, 503rd Infantry Regiment felt small pieces of shrapnel land on their position after the explosion.

The first Iraqis to vote in Ramadi were the security forces and election workers, who began casting their ballots just after the polls opened at 7 a.m. The first two civilian voters came in at 8 a.m., and they were followed shortly after by a group that included two women.

In a tent near the polling station entrance, three female soldiers from the 2nd Forward Support Battalion — which deployed from South Korea along with 4,200 other U.S. troops last fall — helped perform security checks on the female voters who arrived.

Iraqis who voted said through interpreters they were proud to have participated in a day they thought would never happen. The first two women who voted — arriving in long black robes and headdresses — repeatedly said thanks to Allah and shook nearly every hand in sight.

When one of the women placed her ballot in the large plastic collection bin, she turned her eyes and palms skyward, uttering a short prayer.

Soldiers and Marines in Iraq certainly knew they were part of something historic, despite the low turnout in Ramadi.

“I had grandfathers who fought in Korea and World War II, and I don’t think they really knew they were doing something special at the time,” said Marine Lance Cpl. Christopher Green, a dog handler attached to the 1-503rd for election day.

“But I think guys know this is big. This is something important.”