U.S. Defense Department on Thursday announced it will open up over 14,000 positions to women, including those in direct ground combat units, allowing women to serve closer to the battlefield.

In a notification to Congress, the Pentagon said it intends to change a 1994 rule that prohibits women from direct ground combat positions. The Pentagon said because the modern-day battlefield is "non-linear and fluid, with no clearly defined front line or safer rear area, combat support operations are dispersed throughout the battlespace," it is opening up over 13,000 Army positions previously closed to women, such as tank mechanic and field artillery radar operator.

Additionally, the 1994 policy prohibited women from being assigned below brigade level to units whose principal mission was to engage in combat. The Army, Marines and Navy have been granted exceptions to the policy to allow select positions at the battalion level in specialties already open to women, opening 1, 186 additional positions, the department announced.

"Women are contributing in unprecedented ways to the military's mission. Through their courage, sacrifice, patriotism and great skill, women have proven their ability to serve in an expanding number of roles on and off the battlefield," Secretary of Defense Leon Panetta said. "We will continue to open as many positions as possible to women so that anyone qualified to serve can have the opportunity to do so."

Despite the change, the Pentagon still prohibits women from serving in about 238,000 military positions, almost all of them in the Army and Marine Corps.