WASHINGTON — A day after a contested decision to pull American military forces from Syria, officials said Thursday that President Donald Trump has ordered the start of a reduction of American forces in Afghanistan.

More than 7,000 American troops will begin to return home from Afghanistan in the coming weeks, a U.S. official said. The move will come as the first stage of a phased drawdown and the start of a conclusion to the 17-year war that officials say could take at least many months. There now are more than 14,000 U.S. troops in Afghanistan. Trump announced Wednesday that he would pull all of the more than 2,000 American troops from Syria.