KNOXVILLE, Tenn. (WATE) — Tennessee Gov. Bill Lee declared Friday that all flags at the Tennessee State Capitol will fly at half-staff Saturday in honor of Staff Sgt. Ryan Knauss, an East Tennessean killed in the Kabul airport attack in Afghanistan, and the victims of the 9/11 terrorist attacks.

Army Staff Sgt. Ryan Knauss was one of 13 U.S. service members killed by a suicide bomber from the Islamic State on Aug. 26 while they had been aiding to help people to escape Afghanistan amid the withdrawal of American troops. All 13 service members were posthumously awarded Purple Hearts.

His remains arrived in Knoxville Thursday where a convoy escorted him to a funeral home in the Halls community as members of the public lined the route in his honor.

public memorial service is set for Saturday at Gibbs High School. Following the memorial, he will be interred at Arlington National Cemetery in Virginia.

Knauss was a member of the Army’s 82nd Airborne Division and a staff sergeant assigned to the 9th Battalion, 8th Psychological Operations Group. He had joined the Army in May 2016 following his high school graduation.

Saturday will mark 20 years since nearly 3,000 Americans were killed in a series of terrorist attacks on U.S. soil. To honor those who died during the terrorist attack, several groups throughout East Tennessee will be holding memorial events on Sept. 11.