US President Donald Trump’s national security advisor said Friday that the administration has set a timeline for the withdrawal of US forces from Afghanistan by early next year. 

Speaking to a virtual audience at the Aspen Institute, US national security advisor Robert O’Brien said Trump has ordered the Pentagon to reduce troop level to about 2,500 service members in Afghanistan by early 2021. 

“I can guarantee that’s the order of the commander in chief,” O’Brien said, adding that Secretary of Defense Mark Esper was fully on board with Trump’s policy. 

O’Brien’s comments came a week after he and the US president publicly laid out different timelines for the withdrawal of troops from Afghanistan. Trump’s announcement, made via tweet, called for US forces withdrawal by Christmas. 

“The troops always want to be home on Christmas,” O’Brien said. “The president wants them home by Christmas, and what I’ve said on this and I think the president has said as well is that we’d like the troops out as soon as possible.” 

The war in Afghanistan began 19 years ago and has cost $193 billion, according to a Defense Department report. 

“Ultimately, Afghanistan has to be run by the Afghans,” O’Brien said. 

On February 29, the United States signed a peace deal with the Taliban that would usher in a permanent ceasefire and reduce the US military’s presence from nearly 13,000 to 8,600 by mid-July. And by May 2021, all foreign forces would leave Afghanistan, according to the deal. 

The remarks come amidst ongoing peace negotiations between delegates from the Islamic Republic of Afghanistan and the Taliban.