(USA TODAY) - WASHINGTON — President Trump said Wednesday via Twitter that the U.S. military will not accept transgender troops into its ranks or allow them to serve, reversing a policy begun under the Obama administration.

In a series of morning tweets, Trump said that, after consulting "with my generals and military experts," the U.S. government "will not accept or allow transgender individuals to serve in any capacity in the U.S. Military."

The U.S. military, he said, "must be focused on decisive and overwhelming victory and cannot be burdened with the tremendous medical costs and disruption that transgender in the military would entail."

It’s unclear how the announcement will affect the estimated 6,000 transgender troops now serving. Under the policy announced in July 2016, those troops were allowed to serve openly. Prior to that the military discharged them for medical reasons.

Under Trump and Defense Secretary Jim Mattis, the Pentagon delayed implementation of a key portion of the plan: requiring the services to being accepting and recruiting new officers and enlisted troops. The Army, Air Force and Marine Corps requested more time to implement the policy, saying they needed time to study the effects of accepting transgender troops.

However, the Pentagon commissioned a report last year by the non-partisan RAND Corp. on transgender troops. Their research found that treating transgender troops would cost as much as $8 million per year and have a negligible effect on the military’s readiness to fight.

Last month, the Army had begun compulsory transgender sensitivity training for soldiers and civilian employees.

Some members of Congress have also tried to limit spending on transgender troops in this year’s legislation authorizing military spending.

On Tuesday, in a statement to USA TODAY, former Chairman of the Joint Chiefs of Staff, Adm. Mike Mullen urged the acceptance of transgender troops by the military, saying that previous policies that prevented gay and lesbian troops from serving damaged the military.

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