The Trump administration is planning to withdraw thousands of troops from Afghanistan, US media say.
Reports, citing unnamed officials, say about 7,000 troops - roughly half the remaining US military presence in the country - could go home within months.
The reports come a day after the president announced the country's military withdrawal from Syria.
Earlier on Thursday, Mr Trump's defence secretary, Jim Mattis, announced his resignation from his post.
In his letter of departure, Gen Mattis mentioned his diverging views with the president, but did not cite troops withdrawals directly.