(CNN) Secretary of Defense Jim Mattis said Monday that the White House had still not provided policy guidance on transgender persons serving in the military, adding that they were still studying the issue, raising the prospect that transgender service members may be allowed to continue to serve despite President Donald Trump's July announcement of a ban via twitter.

"We are going to study the issue," Mattis told reporters at the Pentagon.

"The policy is going to address whether or not transgenders can serve under what conditions, what medical support they require, how much time would they be perhaps non-deployable leaving others to pick up their share of everything. There's a host of issues and I'm learning more about this than I ever thought I would and it's obviously very complex to include the privacy issues which we respect," Mattis said.

"I am waiting right now to get the President's guidance in and that I expect to be very soon," he added.

Trump announced his plan to ban transgender service members on Twitter last month. The move took the Joint Chiefs of Staff by surprise, and the Pentagon has said it is awaiting an official order from Trump before making a policy change.

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