Washington (Web Desk): Pentagon will send almost 4,000 additional American troops to Afghanistan , says a Trump administration official.

The official said the decision by Defense Secretary Jim Mattis could be announced as early as next week, US media reported.

It follows Trump's move to give Mattis the authority to set troop levels and seeks to address assertions by the top US commander in Afghanistan that he doesn't have enough forces to help Afghanistan 's army against a resurgent Taliban insurgency.

The official wasn't authorised to discuss details of the decision publicly and demanded anonymity.