FILE PHOTO - U.S. army soldiers are pictured as they observe "Swift Response 2017" military drill, a part of "Saber Guardian 2017" exercise, at Bezmer airfield, Bulgaria, July 18, 2017. REUTERS/Stoyan Nenov

WASHINGTON (Reuters) - A transgender recruit has signed a contract to join the U.S. military for the first time since a federal court ruled late last year that the military would have to accept openly transgender people, the Pentagon said on Monday.

Military officials do not know how many transgender people have begun to enlist since Jan. 1, when the Defense Department began accepting openly transgender recruits, but this is the first time one has officially signed a contract to join the military.

“(The Pentagon) confirms that as of February 23, 2018 there is one transgender individual under contract for service in the US Military,” Major David Eastburn, a Pentagon spokesman, said. The person has signed a contract but not yet started basic training.

In a move that appealed to his hard-line conservative supporters, President Donald Trump announced in July that he would prohibit transgender people from serving in the military, reversing former President Barack Obama’s policy of accepting them. Trump said on Twitter at the time that the military “cannot be burdened with the tremendous medical costs and disruption that transgender in the military would entail.”

A number of federal judges - in Baltimore, Washington, Seattle and Riverside, California - issued rulings blocking Trump’s ban. The judges said the ban would likely violate the right under the U.S. Constitution to equal protection under the law.

Late last year, transgender people were allowed for the first time to enlist in the U.S. military, after the Trump administration decided not to appeal the rulings.

Last week, U.S. Defense Secretary Jim Mattis provided his recommendations to the White House on transgender people serving in the military.

Advocates have said they believe dozens, if not hundreds, of transgender people will seek to join an estimated 4,000 already serving.