An Iraq War veteran charged with murdering former US Navy SEAL sniper-turned author Chris Kyle and a friend turned a gun on the pair while they were at a Texas shooting range, authorities said.

Chris Kyle, who was responsible for 160 killings during his career as US Navy Seal sniper, was shot and killed alongside another man at a gun range by a former marine.

Best-selling author and former US Navy SEAL Chris Kyle has been shot dead along with another man on a gun range, police in Texas said.