The U.S. Secret Service is investigating allegations that one of its agents sexually assaulted a female staff member of the office of Vice President Kamala Harris, the agency confirmed Wednesday.

The agent allegedly forced himself onto the woman and groped her in her hotel room after eating a meal and drinking alcohol with her and several other Harris staffers at a restaurant in Green Bay, Wisconsin, during a visit in the past week to scout possible stops for Harris' presidential campaign, Real Clear Politics reported.

When asked about that report, a Secret Service spokesman told CNBC, "The U.S. Secret Service Office of Professional Responsibility is investigating a misconduct allegation involving an employee."

"The Secret Service holds its personnel to the highest standards," the spokesman said in an email. "The employee has been placed on administrative leave pending the outcome of the investigation."

Harris' office, in a statement on the report, told NBC News, "The Office of the Vice President take the safety of staff seriously."

"We have zero tolerance for sexual misconduct. Senior OVP officials were alerted by the USSS about an incident involving an agent and informed that USSS initiated an investigation," Harris' office said. "The Office of the Vice President will not be releasing further information."

Real Clear Politics reported that the agent's actions toward the Harris campaign staffer "were apparently witnessed by other people present."

The incident comes as the Secret Service continues to face sharp criticism for the attempted assassination of Republican presidential nominee Donald Trump on July 13 during a campaign rally in western Pennsylvania.

Trump was nicked by a bullet, one rally attended was killed and two other men were wounded when a gunman who was able to climb up to a roof overlooking the rally site fired at the former president before the shooter was killed by a Secret Service sniper.

On Wednesday, a report issued by the Senate Homeland Security Committee and its Permanent Subcommittee on Investigations found that the Secret Service's advance personnel roles and responsibilities for Trump's rally "were unclear and lacked accountability," and the Secret Service "failed to sufficiently coordinate with state and local law enforcement."

The report also found that Secret Service personnel who were questioned by the committee staff for the report "deflected blame" for the near killing of Trump.