The US Marine Corps is assigning two women to frontline infantry roles, a first for the armed service under new Pentagon rules opening all combat jobs to women.

In a statement Tuesday, the Marine Corps said it had granted requests from two enlisted women to transfer into "ground combat arms specialties." One will become a machinegunner, the other a rifleman.

"Requests like these help the Marine Corps to continue the implementation of gender integration throughout all Military Occupational Specialties," the Marines said.

President Barack Obama's administration decided in 2013 that all combat positions should be open to women by 2016, including the infantry and special operations forces.

The Marines had requested some exemptions, but these were overruled by Defense Secretary Ashton Carter.

It will take some time before the two Marines are placed in their new roles, as a female "leadership cadre" needs to be established in their units at least three months beforehand.

Although women warriors have frequently found themselves in combat situations in Iraq and Afghanistan, they had previously been barred from joining frontline combat roles.

Currently, women account only for about 15.6 percent of the 1.34 million active duty personnel in the Army, Marine Corps, Navy and Air Force.