A Fort Bragg soldier who collapsed during physical training has died.

A spokesman for the 528th Sustainment Brigade said 29-year-old Sgt. Robert Thornton Jr. of Cairo, Georgia, collapsed while running Tuesday, The Fayetteville Observer reports.

The cause of death is unknown and his death is under investigation, according to the report.

Thornton was a power generation equipment repairer who had been part of the brigade’s 112th Signal Battalion since January.

The brigade is part of the 1st Special Forces Command at Fort Bragg and its soldiers support Special Forces, civil affairs and psychological operations for soldiers around the world.

Thornton enlisted in the Army in 2012. He is survived by his wife and two children.

Thornton’s awards and decorations include the Army Commendation Medal with two Oak Leaf Clusters, Army Achievement Medal with one Oak Leaf Cluster, Army Good Conduct Medal, National Defense Medal, Global War on Terrorism Service Medal, Korean Defense Service Medal, Noncommissioned Officer Professional Development Ribbon, Army Service Ribbon, Overseas Service Ribbon, Parachutist Badge and the Air Assault Badge.