WASHINGTON: Captain Kristen Griest became the United States (US) Army's first female infantry officer this week, the Army said, in a milestone for the US 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 gruelling 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 armour branches, both of which face the possibility of combat. The armour 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 US 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 per cent of US forces deployed to Iraq and Afghanistan were women. They represented about 2pc of US military deaths in those wars.