Defense Secretary Jim Mattis is giving the military chiefs another six months to conduct a review to determine if allowing transgender individuals to enlist in the armed services will affect the “readiness or lethality” of the force.

Pentagon spokeswoman Dana White said Mattis made the decision Friday. The delay in allowing the enlistment of new recruits does not affect transgender troops who are already serving openly in the military.

“After consulting with the service chiefs and secretaries, I have determined that it is necessary to defer the start of accessions for six months,” Mattis said in a memo that was sent Friday to the service chiefs and secretaries and was obtained by The Associated Press. “We will use this additional time to evaluate more carefully the impact of such accessions on readiness and lethality.”

In the memo, Mattis said he believes the department must measure “each policy decision against one standard” — whether it affects the ability of the military to defend the nation.

Mattis’ decision formally endorses an agreement hammered out last week by the leaders of the four military services, which rejected Army and Air Force requests for a two-year wait. And it reflects the broader worry that a longer delay would trigger criticism on Capitol Hill, officials familiar with the talks told The AP.

Mattis said the review by the services must be completed by Dec. 1, and he noted that his approval of a delay “does not presuppose the outcome of the review.” He said the additional time will ensure he has “the benefit of the views of the military leadership and of the senior civilian officials who are now arriving in the department.”

Mattis’ decision was met with divided reaction. Read more via AP