WASHINGTON — A 23-year-old sergeant with the Kentucky National Guard on Thursday became the first female soldier to receive the Silver Star — the nation's third-highest medal for valor — since World War II.

Sgt. Leigh Ann Hester, who is from Nashville, Tenn., but serves in a Kentucky unit, received the award for gallantry during a March 20 insurgent ambush on a convoy in Iraq. Two men from her unit, the 617th Military Police Company of Richmond, Ky., also received the Silver Star for their roles in the same action.

According to military accounts of the firefight, insurgents attacked the convoy as it traveled south of Baghdad, launching their assault from trenches alongside the road using rifles, machine guns and rocket-propelled grenades. Hester and her unit moved through enemy fire to the trenches, attacking them with grenades before entering and clearing them.

She killed at least three insurgents with her M4 rifle, according to her award citation. In the entire battle, 26 or 27 insurgents were killed and several more were captured, according to various accounts. Several Americans were also wounded in the firefight.

"Her actions saved the lives of numerous convoy members. Sgt. Hester's bravery is in keeping with the finest traditions of military heroism," her award citation reads.

"I'm honored to even be considered, much less awarded, the medal," Hester told the American Forces Press Service, a military-run information service. "It really doesn't have anything to do with being a female. It's about the duties I performed that day as a soldier."

Hester, a native of Bowling Green, Ky., joined the Kentucky Army National Guard in April 2001 and moved to Nashville in 2003, according to a biography provided by the Army. She works as a retail store manager. Her unit deployed to Iraq in November 2004 and remains in the Baghdad area, escorting convoys and assisting the Iraqi Highway Patrol.

Also receiving the Silver Star for that action was Staff Sgt. Timothy Nein of Henryville, Ind., and Spc. Jason Mike of Radcliff, Ky. Five other members of their unit received other medals for the action, including another woman, Spc. Ashley Pullen of Edmonton, Ky.

The awards to Hester and Pullen come only weeks after some Republicans in Congress abandoned an effort to curtail the roles of military women in combat zones. The Pentagon and some Democrats and other Republicans opposed the measure.

Current Pentagon policy prohibits women from serving in frontline combat roles — in the infantry, armor or artillery, for example. But the nature of the war in Iraq, with no real front lines, has seen women soldiers take part in close-quarters combat more than in any previous conflict.