Image copyright AFP/US MARINE CORPS Image caption The lieutenant will lead a platoon of 40 Marines in combat

A female US Marine has made history by becoming the first woman to complete the Corps' famously gruelling infantry officer training.

The lieutenant, who wants to keep her identity private, graduated in Quantico, Virginia, on Monday.

She will soon be assigned to lead a 40-strong platoon.

Marine Corps commandant Gen. Robert Neller tweeted a picture of the woman, saying he was "proud of this officer & her fellow leaders".

There are almost 1.4 million active duty troops in the US armed forces, and about 15% are female.

In March 2016, then-President Barack Obama opened all military positions to women, including combat units.

The 13-week officer training course started in July with 131 Marines, and 88 ultimately graduated.

The Corps says it educates would-be officers in "the leadership, infantry skills, and character required to serve as infantry platoon commanders".

Traditionally around a quarter of all applicants miss the mark, 10% of them on the first day.

Media playback is unsupported on your device Media caption The training covers leadership and infantry skills

The Corps has pushed harder to appeal to female recruits this year, after a nude photo scandal saw some Marines share naked photographs of female colleagues on Facebook.

In May it stoutly defended a recruitment advert - the first led by a woman - after critics said it pandered to political correctness.

In an opinion piece for the New York Times, former Marine captain Teresa Fazio said the female officer would be a major asset in Afghanistan.

"Female troops are invaluable for searching houses and communicating with local women, gaining access to spaces and information that, because of local custom, male troops cannot get," she wrote.

The Marine Corps tweeted a video showing the female officer engaged in exercises in the mountains alongside her male counterparts.

She will now be sent to the 1st Marine Division at Camp Pendleton, California, for her first assignment.