Outgoing US Defense Secretary Leon Panetta announced the move in a statement on Thursday.

"The Department's goal in rescinding the rule is to ensure that the mission is met with the best-qualified and most capable people, regardless of gender," Panetta said.

"Women have shown great courage and sacrifice on and off the battlefield, contributed in unprecedented ways to the military's mission and proven their ability to serve in an expanding number of roles."

The White House says Obama is supportive of the measure. Press Secretary Jay Carney told reporters Thursday that the president believes the country should continue to remove "unnecessary gender-based barriers to service."

The policy change is expected to mainly apply to the Army and the Marine Corps, which recently opened infantry officer training to women.

The Air Force and Navy have already lifted most prohibitions, with women already finding themselves in battlefield incidents when they are "attached" to ground units in situations where clear front lines no longer exist.

The move removes another societal barrier in the US armed forces. In 2011, the Pentagon scraped its "Don't Ask, Don't Tell" ban on gays and lesbians serving openly in the military.

Female casualties 2 percent

During the 1990-91 Gulf war women served aboard aircraft, helicopters and naval ships. Since the US-led invasions of Afghanistan and Iraq in 2001 and 2003, 84 US servicewomen have been killed in hostile incidents. That represents about 2 percent of US casualties in Afghanistan and Iraq.

Women currently make up 14.5 percent of US troops on active duty, or about 204,000 people, according to Pentagon data. Over the past 11 years, 300,000 have been deployed in war efforts.

Pressure from rights groups

Last November, the American Civil Liberties Union filed a suit to press the Pentagon to end the combat exclusion policy adopted in 1994. Right-leaning commentators, however, questioned whether mothers in uniform - especially single parents - should be sent into combat.

Democratic lawmaker Tammy Duckworth, a former Black Hawk helicopter pilot who lost both her legs in the Iraq war, hailed the change.

"America's daughters are just as capable of defending liberty as her sons. Lifting the ban on women in combat is good for our nation," Duckworth said in a social network message.

Women already serve several countries in combat roles, notably in Israel and Canada. In 2010, Britain decided it would not change rules excluding women from infantry and combat teams. Officials say demand from women for jobs in the military alliance NATO remain very low.

ipj/msh (Reuters, AFP, AP)