Updated

A retired Navy veteran who's challenging Arlen Specter in Pennsylvania's Democratic primary has asked Vice President Joe Biden to denounce a Specter ad that suggests the military fired him.

Philadelphia-area congressman Joe Sestak asked the vice president in an open letter Thursday to disavow an ad that claims Sestak was relieved of duty "for creating a poor command climate."

Biden is scheduled to headline a Friday rally for Specter in northeastern Pennsylvania.

The Specter ad relies on information in a 2005 Navy Times article. Sestak disputes the report's accuracy and accuses Specter of using "Swift Boat"-style tactics. The retired vice admiral accuses says a contingent of veterans will travel to Scranton on Friday to deliver the letter to Biden.