NASHVILLE, Tennessee (Reuters) - A U.S. soldier opened fire on a group of fellow soldiers during a morning exercise session at Fort Campbell, Kentucky, on Thursday but no one was injured at the Army base.

The soldier, whose name was not released, "is in custody after firing shots at a physical training formation" but no one was wounded, Fort Campbell said in a statement.

It provided no other details but said the matter was under investigation.

The facility, on the Kentucky-Tennessee border about 60 miles northwest of Nashville, is home to the 101st Airborne Division that has served in