(VOVworld) - The head of the US Secret Service has resigned amid increasing criticism over last week’s scandal in which strangers scaled the fence to break into the White House. In a congressional hearing on Wednesday, Julia Pierson admitted that the incident was unacceptable, and she had to take full responsibility over the security lapses in protecting US President Barrack Obama. She told the hearing that Homeland Security secretary Jeh Johnson had accepted her resignation letter.