HARRISBURG, Pa. (AP) – Mehmet Oz’s rivals in Pennsylvania’s Republican primary for U.S. Senate are escalating their attacks on the celebrity heart surgeon’s connections to his parents’ native country of Turkey, raising it as a possible national security issue. Oz, best known as TV’s Dr. Oz, has rejected any suggestions he is a threat to national security and has accused his opponents, particularly GOP rival David McCormick, of making “bigoted attacks.” If elected, Oz would be the nation’s first Muslim senator. The criticism of Oz and his ties to Turkey has mushroomed in the weeks after Oz won the endorsement of former President Donald Trump, who remains deeply popular with conservative voters.