Sen. Lindsey Graham, a prominent Republican member of the Armed Services Committee, warned President Trump on Friday not to give up on Afghanistan.

"If we were to pull all our troops from Afghanistan it would be a disaster for our national security interests and set the stage for another 9/11 on American soil," Graham said in a statement issued Friday, as Trump huddled with his national security team at Camp David to review options for the almost 16-year-long war.

Defense Secretary Jim Mattis, Secretary of State Rex Tillerson, Vice President Mike Pence, and national security adviser H.R. McMaster are among the 21 advisers meeting at the presidential retreat in the Catoctin mountains of Maryland reviewing a Pentagon plan to send several thousand additional U.S. and NATO military trainers to support Afghan troops.

Approval of the plan has been delayed by Trump, who is questioning the wisdom of sending additional troops to a war that has little prospect of ending anytime soon.

"I encourage President Trump to listen to his generals," Graham said. "I hope President Trump, unlike his predecessor, will not put our military in a bad spot in Afghanistan."

Not present at the Camp David strategy session was Steve Bannon, who is leaving the White House and who was said to be the prime advocate of an alternative plan to use contract security forces, including a private air force instead of U.S. troops.