After 19 years, U.S. military women soldiers wanting to engage in direct frontline combat as their ultimate service and sacrifice to their country will now become a reality as the Pentagon on Wednesday terminated its ban on women serving in front-line combat roles.

The new policy is expected to be formally announced by US Defense Secretary Leon E. Panetta later on Thursday.

"This policy change will initiate a process whereby the services will develop plans to implement this decision, which was made by the Secretary of Defense upon the recommendation of the Joint Chiefs of Staff," an unidentified US senior defence official was quoted by media reports. The policy will take effect by 2016.

With the policy change, thousands of front-line combat positions to women in all U.S. military services are expected to open up, including the Army, Navy, Air Force, Marines and Coast Guard. To accommodate the influx, U.S. military chiefs are given until May to map plans for implementing the new policy.

"This is an historic step for equality and for recognizing the role women have, and will continue to play, in the defense of our nation," U.S. Senator Patty Murray said.

Carl Levin, another U.S. senator and head of the Senate Armed Services Committee, who likewise acknowledged the big leap, said the move reflected the "reality of 21st century military operations."

In a report to the U.S. Congress, defence officials said some of the military's gender-based restrictions have become obsolete if based on the experience of the U.S. troops in Iraq and Afghanistan. They said the battlefields there had no clear front lines as well as no limit to exposure to the fighting.

"This policy has become irrelevant given the modern battlespace with its nonlinear boundaries," the Defense Department told Congress.

At least 300,000 women soldiers have been deployed in the U.S. forces in the Iraq and Afghanistan wars over the past 11 years. But they were not allowed to serve in the infantry, armor and special operations units whose main functions were involved in front-line combat.

And while the U.S. military ponders how to implement the new policy, the accompanying slideshow shows some of the world's famous women soldiers.

Afghanistan Iraq Coast Guard