U.S. President Donald Trump has given Defense Secretary Jim Mattis the authority to set troop levels in Afghanistan, a U.S. official told Reuters on Tuesday, opening the door for future troop increases requested by the U.S. commander.

The official, who spoke on condition of anonymity, said no immediate decision had been made about the troop levels, which are now set at about 8,400.

The Pentagon declined to comment.

The decision is similar to one announced in April that applied to U.S. troop levels in Iraq and Syria, and came as Mattis warned Congress the U.S.-backed Afghan forces were not beating the Taliban despite more than 15 years of war.

“We are not winning in Afghanistan right now,” Mattis said in testimony to the Senate Armed Services Committee earlier on Tuesday. “And we will correct this as soon as possible.”

Mattis said the Taliban were “surging” at the moment, something he said he intended to address.

A former U.S. official said such a decision might allow the White House to argue that it was not micromanaging as much as the administration of former President Barack Obama was sometimes accused of doing.

Read the whole story from Reuters.