WASHINGTON - The Secret Service prostitution scandal grew Monday to include a 12th member of the U.S. military as the Pentagon suspended the security clearances of all the military personnel who have been implicated. The Secret Service has also taken action against 12 of its employees.

Three Defense Department officials said the 12th military person involved was in Colombia in advance of President Obama's arrival for the Summit of the Americas and was assigned to the White House Communications Agency, a military unit that provides secure communications for the president. The defense officials, who spoke on the condition of anonymity because the investigation is ongoing, said he is an enlisted man. One of the officials said he is in the Army.

Another of the officials said the soldier has been relieved of his duties at the White House.

Meanwhile, the White House still faced criticism Monday because of the scandal, and it moved anew to keep itself at arm's length. Led by its top lawyer, the White House internally investigated and then ruled out misconduct by the White House staff members who helped arrange the president's trip to Colombia. Obama's chief spokesman, Jay Carney, sought to make clear that the White House Communications Agency, which has now been implicated by the widening scandal, is a military unit and not a White House one.

Defense Secretary Leon Panetta said the Pentagon had suspended the security clearances of the dozen military members under investigation in the scandal. The Secret Service had previously revoked the top-secret clearances for the officers involved.

Six Secret Service employees, including two supervisors, have been forced out of the agency amid the scandal, which erupted the morning of April 12 when a fight over payment between a Colombian prostitute and a Secret Service officer spilled into the hallway of the Hotel Caribe. The officers were part of Obama's advance security team in Cartagena. One officer was cleared of serious wrongdoing but will face administrative action, the agency said Friday. The remaining five officers have been suspended.

The Secret Service and investigators from U.S. Southern Command, which organized the military contingent for the security team in Colombia, have been investigating the incident, which involved as many as 20 Colombian women.

A lawyer for the two ousted supervisors, Greg Stokes and David Chaney, has said that whatever may or may not have been happened at the Hotel Caribe did not ct the officers' mission or compromise the president's security. No other agent or member of the military has been named.