According to a US official, President Donald Trump just ordered the more than 2,000 American troops stationed in Syria to be withdrawn as soon as possible.

Trump's decision came after the mission against the Islamic State was completed, according to the official, who spoke on condition of anonymity as he was not authorized to speak publicly before an official announcement, USA Today reports.

White House press secretary Sarah Sanders said Wednesday that the U.S. has "defeated the territorial caliphate."

The commander-in-chief declared victory over the Islamic State in Syria in a tweet on Wednesday morning. “We have defeated ISIS in Syria, my only reason for being there during the Trump Presidency,” he wrote.

However, while President Trump has ended the war against the Islamic State, U.S.-led forces continue to fight down there. According to the U.S. Central Command, a total of 47 airstrikes were conducted by war planes against ISIS targets on Saturday. During the targeted attack, over 20 ISIS fighting units, petroleum tanks, a tunnel, vehicle, and a mortar-firing position were destroyed by bombs.

That said, according to a recent report by the Washington-based Center for Strategic and International Studies, ISIS may still possess anywhere between 20,000 to 30,000 militants in Iraq and Syria.

Officials said as recently as last week that U.S. troops may need to stay for a longer period to ensure the military's accomplishments were "enduring."

Brett McGurk, Special Presidential Envoy for the Global Coalition to Defeat ISIS, said, "I think it's fair to say Americans will remain on the ground after the physical defeat of the caliphate until we have the pieces in place to ensure that that defeat is enduring."

Earlier this month, Marine Gen. Joseph Dunford, chairman of the Joint Chiefs of Staff, suggested U.S. troops may be needed for some more time to establish conditions for a long-term peace agreement. "We still have a long way to go and so I'd be reluctant to give a fixed time," Dunford said during a forum held by The Washington Post.

Since 2014, U.S. troops belonging to special operations units have been training local security forces in eastern Syria as the U.S.-led coalition was fighting ISIS.

Speaking to reporters in September, Defense Secretary Jim Mattis said U.S. forces had helped deter Iran from increasing its footprint and influence in the war-torn region. Having said that, the U.S.' primarily objective has been to push back ISIS enough so that the United Nations can step in and broker a peace plan that would end years of infighting that have claimed the lives of hundreds of thousands of innocent civilians and given rise to a refugee crisis.

“We want to support the Geneva process, the U.N.-mandated process,” Mattis said at the time. “In that scope what we want to do is make certain that ISIS does not come back and upset everything again.”