U.S. President Donald Trump waves as he walks on the South Lawn of the White House, August 20, 2017. REUTERS/Yuri Gripas

WASHINGTON (Reuters) - President Donald Trump has signed off on sending 4,000 more troops to Afghanistan, Fox News reported on Monday, citing a senior U.S. official.

The report comes before Trump addresses the nation on his strategy for Afghanistan at 9:00 p.m. EDT Monday (0100 GMT on Tuesday).