Captain Kristen Griest (R) participates in an obstacle course during training at the U.S. Army Ranger School on Ft. Benning Georgia, June 23, 2015. REUTERS/U.S. Army/Staff Sgt. Scott Brooks/Handout

WASHINGTON (Reuters) - Captain Kristen Griest became the U.S. Army’s first female infantry officer this week, the Army said, in a milestone for the U.S. military as it opens up combat roles for women.

Griest was one of two women who made history last year after becoming one of the first female soldiers to pass the Army’s grueling course to qualify for the elite Rangers unit.

Earlier this month, the Army said it had approved requests from more than 20 women to enter the infantry and armor branches, both of which face the possibility of combat. The armor branch includes tanks.

Army Times, which first reported the news, said Griest was expected to graduate from the Maneuver Captain’s Career Course on Thursday.

Last year the U.S. military said it would let women serve in all combat roles, a historic move striking down gender barriers in the armed forces.

As of mid-2015, nearly 12 percent of U.S. forces deployed to Iraq and Afghanistan were women. They represented about 2 percent of U.S. military deaths in those wars.