TALLAHASSEE, Fla. (AP) - Florida serial killer David Gore is asking the U.S. Supreme Court to block his impending execution.

Gore's lawyers asked for a stay and filed an appeal on Tuesday, just two days before he is scheduled to die.

He is set for execution by lethal injection Thursday for murdering 17-year-old Lynn Elliot in Indian River County nearly 30 years ago. Gore also is serving life terms for killing five other girls or women.

The appeal is based on a recent U.S. Supreme Court ruling that says federal courts must hear a convict's claim of receiving ineffective legal assistance - or none at all - for appeals alleging the inmate's trial lawyers also had been ineffective.

The Florida Supreme Court rejected a similar appeal Monday.