Florida put to death Thursday a man convicted of the rape and murder of an 11-year-old girl, authorities said, the state's seventh execution this year.

Eddie Davis, 45, who spent 20 years on death row, was declared dead by lethal injection at 6.43pm (2243 GMT), Florida prisons spokeswoman Jessica Cary told AFP.

His final appeals to the Supreme Court -- arguing the new drug protocol in Florida could subject him to unconstitutional suffering -- were rejected at the last minute, according to court documents.

Davis was sentenced to death for raping and suffocating to death in 1994 his ex-girlfriend's daughter. He had kidnapped the girl while she was sleeping in her mother's bed -- while her mother was working a night shift at a hospital.

He molested and raped her in the trailer where he lived nearby and suffocated her with a plastic bag before throwing her body in the trash.

Davis was the 24th inmate executed this year in the United States, where controversy over lethal injections was sparked after a botched execution in Oklahoma, in which the inmate took 43 minutes to die and during which he was seen to be writhing in pain.

This was also the second execution this month in Florida, which just changed its drug protocol for lethal injections. The state has put seven men to death this year, the same number as in Texas, which generally holds the US record for most executions.

Meanwhile, in Georgia, Tommy Waldrip, also scheduled to be put to death Thursday, had his sentence commuted to life in prison without parole.

Twenty-six hours before the execution, the Georgia Board of Pardons and Paroles made the rare decision to grant clemency, after all of Waldrip's appeals had been exhausted.

Waldrip was convicted of the 1991 murder of a student who was supposed to testify in his son's trial for armed robbery.