In remarks at the State Department, Mattis told reporters President Donald Trump will confer with his national security team tomorrow at the Camp David presidential retreat in Maryland, and said the talks "will move this toward a decision."
"We are coming very close to a decision, and I anticipate it in the very near future," he added.
The administration has said its Afghanistan strategy will be informed by a review of its approach to the broader region, including Pakistan and India. The Taliban have long used Pakistan as a sanctuary, complicating efforts to defeat the insurgency in Afghanistan and stabilize the country.
More From This Section
Government forces also are battling an Islamic State affiliate that has carved out a foothold mostly in eastern Afghanistan. Trump has vowed to crush IS, so the affiliate in Afghanistan poses an additional challenge with no immediate solution. Just this week, a US soldier was killed and nearly a dozen were wounded in combat with the IS affiliate.
The US has about 8,400 troops in Afghanistan. Their primary roles are to train and advise Afghan forces and to hunt down and kill members of al-Qaida and other extremist groups.
Asked Monday if Trump has confidence in Nicholson, Mattis demurred.
"Ask the president," Mattis said. "I will tell you right now, he is our commander in the field, he has the confidence of NATO, he has the confidence of Afghanistan, he has the confidence of the United States."
Trump is "looking at all aspects" of US involvement in Afghanistan "as he must in his responsibilities as the commander in chief," Mattis said.
"Nearly seven months into President Trump's administration, we've had no strategy at all as conditions on the ground have steadily worsened," said McCain, chairman of the Senate Armed Services Committee. "The thousands of Americans putting their lives on the line in Afghanistan deserve better from their commander in chief."