Washington, Aug 25 (IANS): Florida has executed an inmate for the first time in more than 18 months, administering a lethal injection drug that had not previously been used in the US, the media reported.

Mark Asay, 53, was executed at 6.22 p.m. (local time) on Thursday without any incident, CNN quoted Florida corrections officials as saying.

Asay had no last statement, and did not speak or show any indication of pain during the execution. His demeanour earlier in the morning was calm, a Florida corrections department spokeswoman said.

The US Supreme Court earlier on Thursday denied a stay of execution request for Asay.

He was convicted in 1988 of the racially motivated murders of two men in Jacksonville the previous year.

A jury found him guilty of killing Robert Lee Booker -- who was black -- and Robert McDowell.

Before he shot Booker, he called him a racial epithet, CNN reported.

The execution marked Florida's first since a US Supreme Court ruling temporarily halted the practice in early 2016, saying the state's sentencing process was unconstitutional because it gave judges, rather than juries, too much power in deciding whether to execute an inmate.

The state used etomidate as one of three drugs in the lethal injection, marking the first time the sedative has been used in an execution.

Etomidate will be a substitute for midazolam, a drug that has become harder to get because some drug manufacturers do not want it used in executions.