MIAMI (AP) — The looming presidency of Donald Trump has created a deep sense of uncertainty for inmates at Guantanamo on the 15th anniversary of the arrival of the first prisoners at the U.S. base in Cuba.

Nineteen of the remaining 55 prisoners are cleared for release and could be freed in the final days of Barack Obama's presidency, part of an effort to shrink the prison since the administration couldn't close it on his watch.

But those left behind will face the future under Trump, who has said he wants to keep Guantanamo open and recently called on Obama to halt releases.

"There is a great deal of anxiety and fear," said Pardiss Kebriaei, a lawyer with the Center for Constitutional Rights, a New York-based organization that represents five prisoners.

That backdrop has given a feeling of urgency to anti-Guantanamo demonstrations scheduled for Wednesday's anniversary in London, Los Angeles and Washington, featuring activists in the orange prison jumpsuits that came to symbolize the detention center though now they are typically worn only by a handful of detainees who have violated detention center rules and are on "disciplinary status."

In Washington, human rights groups, including Amnesty International USA, plan to rally at the Supreme Court and then march to the Senate as they demand Obama use his executive powers to override congressional restrictions on moving detainees to the U.S. and close the detention center before Trump's Jan. 20 inauguration, an unlikely prospect given it would face legal challenges and could be reversed once Trump takes office.

"We want to see everyone in Guantanamo charged and fairly tried or released," said Elizabeth Beavers, senior campaigner with Amnesty. "That's what we see as the only lawful disposition."

The U.S. began using its military base on southeast Cuba's isolated, rocky coast to hold prisoners captured during the Afghanistan invasion, bringing the first planeload on Jan. 11, 2002, and reaching a peak 18 months later of nearly 680. There were 242 prisoners left when Obama took office in 2009, pledging to close what became a source of international criticism over the mistreatment of detainees and the notion of holding people indefinitely, most without charge.

Obama was unable to close Guantanamo because of American opposition to holding any of the men in the United States. That ultimately became a ban on transferring them to U.S. soil for any reason, including trial, making the failure to close the detention center part of his legacy.

Trump said during the campaign that he not only wants to keep Guantanamo open but "load it up with some bad dudes." He weighed in on Twitter on Jan. 3, saying: "There should be no further releases from Gitmo. These are extremely dangerous people and should not be allowed back onto the battlefield."

Two days later, the Pentagon announced four men held for more than 14 years without charge had been released and transferred to Saudi Arabia for resettlement. White House spokesman Josh Earnest rejected the president-elect's call for a halt to releases and said more would follow in the coming days.

"He'll have an opportunity to implement the policy that he believes is most effective when he takes office on Jan. 20," Earnest said.

The 55 remaining prisoners include 10 who are in some stage of the military commissions, a hybrid of civilian and military court set up to prosecute men at Guantanamo for war crimes. One, an aide to Osama bin Laden, was convicted and is serving a life sentence; two are awaiting sentences as part of plea deals; and the other seven are in the pre-trial stage, including five men charged in the Sept. 11, 2001, attack.

With the 19 cleared to go, that leaves 26 being held under international laws of war that the U.S. government says allows it to detain men indefinitely if they pose a threat to the country or its allies. For the most part, they can't be charged either because there isn't adequate evidence or the only evidence that exists is tainted because it was obtained by torture or because courts say their alleged offenses aren't international war crimes and could only be prosecuted by a civilian court in the United States, which is prohibited by Congress.

The Obama administration has cut the number of these prisoners by more than half through parole-like hearings that re-evaluate detainees. Some fear these will halt under Trump.

"I do think it will be a little while before we see the next full review," said Shane Kadidal, a detainee lawyer with the Center for Constitutional Rights.

Trump has not specified his plans for managing the detention center, and some lawyers for detainees, such as Shelby Sullivan-Bennis of the human rights group Reprieve, said it's possible the new president will retain some current policies once his administration has studied them.

"At this point, we are all just keeping our fingers crossed for the best outcome," she said.