The U.S. Marine Corps is expected to request that women continue to be barred from certain front-line jobs, putting Marine and Navy leaders on a collision course over letting women take on combat roles across the U.S. armed services, the Associated Press reported Friday. All branches of the U.S. military have until January to provide the Department of Defense with scientifically backed reasoning for why they require an exemption from allowing women into front-line combat roles.

The Marines' decision, which is not yet set in stone, has raised questions about whether Navy Secretary Ray Mabus, who supports opening all positions to women, can veto the Marine Corps position on the issue. It also pits Gen. Joseph Dunford, the Marine Corps commandant who will take over as chairman of the Joint Chiefs of Staff next week, against the three other military services, which are likely to open up all positions to women. Dunford will be in the unusual position of being able to approve or deny the request from the Marines that he submitted while commandant of the Corps.

The Army, Navy and Air Force are not expected to ask Defense Secretary Ash Carter for any exemptions, while the Special Operations Command is also expected to allow women to serve in its toughest roles. But it may take years before the Special Forces are able to open up those positions to women, according to officials who spoke with the AP.

Because the Marine Corps is part of the Navy, Mabus is secretary of both services and may look to overrule Dunford. On Monday, Mabus outlined his position on the matter.

"I'm not going to ask for an exemption for the Marines, and it's not going to make them any less fighting-effective," he said, adding that the Navy SEALs also will not seek any waivers. "I think they will be a stronger force because a more diverse force is a stronger force. And it will not make them any less lethal."

Mabus’ comments angered Rep. Duncan Hunter, R-Calif., who demanded in a letter to Carter that Mabus resign because he “openly disrespected the Marine Corps as an institution, and he insulted the competency of Marines by disregarding their professional judgment, their combat experience and their quality of leadership."

Under current plans, military branch leaders will present their plans for women to serve on the front lines to service secretaries, who will then pass them to Carter for review. He will make a decision by the end of the year.