The attorney for convicted sniper John Allen Muhammad says he plans to ask for clemency for his client, who's scheduled for execution next month.

Jonathan Sheldon plans to file the request next Thursday with Gov. Timothy Kaine, according to an announcement on his law firm's Web site. Sheldon also plans to file an appeal with the U.S. Supreme Court.

Kaine previously has said he's unlikely to grant clemency but would review Muhammad's request.

Muhammad was sentenced to death for the October 2002 slaying of Dean Harold Meyers at a Manassas gas station during a string of shootings that left 10 people dead and three wounded in Virginia, Washington, D.C., and Maryland.

Muhammad's teenage co-defendant Lee Boyd Malvo is serving a life sentence.