The state of Texas has executed a Mexican national despite pleas from the White House that the action would break international law.
The US Supreme Court rejected a last-minute stay of execution for Humberto Leal Garcia.
The 38 year old, who has lived in the US since he was an infant, was convicted of raping and murdering a 16 year old girl in 1994.
Garcia was given a lethal injection at a prison in Huntsville, Texas.
The Obama administration warned that executing Leal Garcia would violate the Vienna Convention on Consular Relations and leave US citizens travelling abroad at higher risk of arrest without cause or denial of diplomatic representation.