The White House has said it does not know what will happen to transgender service members currently serving in the US military, following President Donald Trump's sudden announcement that the government "will not accept or allow Transgender individuals to serve in any capacity in the U.S. Military".

The President announced his decision in a stream of tweets on Tuesday morning, writing: "Our military 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".

Asked whether this meant active transgender troops would be sent home, White House Press Secretary Sarah Huckabee Sanders responded: “That’s something that the Department of Defence and the White House will have to work together as implementation takes place and is done so lawfully."

When reporters pressed for further details on the policy, Ms Huckabee Sanders threatened to shut the briefing down.

The comments seemed to indicate that the White House does not know what will happen to the more than 2,500 transgender people actively serving in the US military as a result of their policy.

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Ms Hucakbee Sanders said the decision – which she defended as purely tactical – was made after "extensive discussions" with Mr Trump's national security team.

The Pentagon press department, however, seemed caught off guard after the announcement this morning, and referred all comment to the White House. A version of their transgender enrollment timeline was still accessible online at the time of the announcement.

Ms Huckabee Sanders said Defence Secretary James Mattis was informed of the decision immediately after the President made it, one day before it was announced.

“I think sometimes you have to make decisions," the Press Secretary said. "And once [Mr Trump] made a decision, he didn’t feel it was necessary to hold that decision.”

The decision ended an Obama-era policy allowing current transgender service members to serve openly, receive medical care, and change their gender identity in the Pentagon’s personnel system.

The Trump administration had been weighing for months whether or nor to roll out the final phase of this policy, which would allow new, openly transgender recruits to enlist. Just last month, Defence Secretary Jim Mattis had requested six more months to consider the roll-out.

According to Politico, however, Mr Trump made the final decision quickly, in a last-minute attempt to save a spending bill that would his proposed border wall with Mexico.

The funding bill was threatened by disagreements among House Republicans about a proposed ban on Pentagon-funded sex reassignment operations. Some wanted to include the ban in the bill, while others found it discriminatory.

In an effort to save the bill – and the funding for his border wall – Mr Trump made the decision to ban transgender service altogether. He took to Twitter, and, with the stroke of a keyboard, reversed years of Pentagon policy.