Image copyright Alabama Dept of Corrections/AFP

The US state of Alabama has executed a Muslim inmate after the Supreme Court dismissed his appeal for an imam to be present with him at death.

Convicted murderer Dominique Ray was killed by lethal injection on Thursday as scheduled.

Ray's lawyers had argued that the state favoured Christians because a chaplain was allowed to be in the room with inmates.

Imam Yusef Maisonet instead watched from an adjacent room, reports said.

On Wednesday a federal appeals court agreed to a temporary delay to the execution, saying in its judgement that Ray had a "powerful" claim against the state because it refused to "provide the same benefit to a devout Muslim and all other non-Christians".

However Alabama quickly appealed to the Supreme Court, which ruled five to four in its favour.

The Alabama Department of Corrections (ADOC) employs a Christian chaplain who has been in the execution room for nearly every execution since 1997 - but ADOC refused to allow a non-employee to be in the execution chamber instead of the chaplain.

Ray had been an inmate for close to 20 years, the New York Times reported, and converted to Islam while in prison.

He was sentenced to death in 1999 for raping and murdering a 15-year-old girl in 1995.