A Cuban-born man identified as a leader of a Hispanic prison gang has been executed for the robbery-murder of a Houston drug dealer more than 10 years ago.

Yosvanis "El Cubano" Valle denied fatally shooting 28-year-old Jose Martin Junco at a Houston home in June 1999 but said there was little he could do to avoid lethal injection.

On Tuesday evening, 34-year-old Valle became the 21st inmate executed in Texas this year.

Court documents showed the June 1999 holdup was a test devised by Valle to see if a gang member had the courage to shoot Junco.

The Texas Board of Pardons and Paroles last week rejected a request from Valle's lawyers that his death sentence be commuted to life in prison.