Republican Sen. Scott Brown hasn't said whether he'll run for John Kerry's Senate seat, but he's already taking a shot at a possible Democratic rival.

Brown, who lost his re-election battle last year to Elizabeth Warren, questioned how much time U.S. Rep. Edward Markey spends in Massachusetts.

Markey, a Malden Democrat, has said he'll run for Kerry's seat if Kerry is confirmed as secretary of state.

Speaking on WTKK-FM Wednesday, Brown said of Markey, "Does he even live here?" Markey and his wife own Markey's boyhood home in Malden, but also own a home in Chevy Chase, Md.

A Markey campaign aide accused Brown of launching "false, personal attacks" and said Markey has lived in Malden his entire life.

Brown, who also owns a home in Washington, said he has been flying home from Washington every weekend for nearly three years and has never seen Markey on an airplane.