PHILADELPHIA - The U.S. Secret Service has issued an alert for a man reportedly headed to the White House in a vehicle believed to be filled with explosives.

The Secret Service confirms to WTOP that it has issued an alert, but would not be specific about the type of vehicle being sought. D.C. Police and the U.S. Capitol Police tell WTOP they are aware of the alert.

The Secret Service tells CBS Chief White House Correspondent John Roberts that the alert was issued for a man in a rental van, possibly one filled with explosives.

But KYW Radio in Philadelphia reports that Philadelphia Police, in a "general radio message," say the man is traveling in an Enterprise rental car -- a 2001 Chevrolet Cavalier with Pennsylvania license tag number "DVT-0196."

The suspect is identified as Jeffrey Clutier, who is thought to be wearing a white t-shirt, blue jeans, and bedroom slippers, KYW reports. Philadelphia Police tell KYW the man was last seen in Lester, Pa.

The Secret Service has told Philadelphia Police the man may be in the company of girlfriend and a brown dog, the station reports.