WASHINGTON (REUTERS) - The first female director of the United States (US) Secret Service, Ms Julia Pierson, was sworn in at the White House on Wednesday during a short ceremony that marked a historic shift for the agency charged with protecting the president.

Vice-President Joe Biden administered the oath of office to Ms Pierson, with President Barack Obama standing at their side.

"Obviously, she's breaking the mold in terms of directors of the agency, and I think that people are all extraordinarily proud of her," Mr Obama told reporters at the end of the ceremony.

She has extraordinary qualifications, and I think a lot of people who have worked with Julia know how dedicated, how professional, how committed she is, and I think are absolutely certain that she's going to thrive in this job," he said.

Mr Biden, who has a reputation for making occasional gaffes, said the agents who protect him were "excited that we picked her".

The Secret Service has been criticised for having an insular, male-dominated culture, and its reputation was tarnished by a 2012 scandal involving its agents and prostitutes in Colombia.