A 44-year-old white supremacist has been executed in Texas for killing a black man by dragging him behind a truck.

John William "Bill" King was put to death by lethal injection at the state's death chamber in Huntsville, the Texas Department of Criminal Justice said in a statement.

The department said King wrote a last statement that read: "Capital Punishment: Them without the capital get the punishment."

King, along with Shawn Berry and Lawrence Brewer, was accused of kidnapping James Byrd Jr while he hitchhiked in Jasper, Texas, on 7 June, 1998.

Lawrence Brewer was executed in 2011 for the murder, while Shawn Berry, who cooperated with investigators, was given life in prison.

King had claimed that Mr Byrd's death was not a hate-fuelled murder but a drug deal gone wrong.

Prosecutors said the men dragged him behind their pickup truck for 5km, before dumping his body in front of an African-American church.

A "KKK" engraved lighter was among the evidence police found at the scene, court documents showed.

The gruesome killing spurred the passing of the James Byrd Jr Hate Crimes Act, strengthening punishments for hate crimes in Texas.

King was found guilty of capital murder and sentenced to death in 1999.

He was a member of a white supremacist gang and spoke of starting a race war while in prison for a previous crime.

He also talked about initiating new members by having them kidnap and murder black people, court documents showed.