The U.S. Secret Service is investigating how an intruder was able to get into the home of National Security Adviser Jake Sullivan last month undetected by those charged with protecting him and his family.
The man walked into Sullivan's Washington, D.C., home in the middle of the night around 3 a.m. sometime in April without being detected by agents.
Sullivan, who has 24/7 Secret Service protection, confronted the man, who left after being asked to leave.
The Secret Service said it was investigating the incident.
"Secret Service is examining a security incident that took place at a protectee site. While the protectee was unharmed, we are taking this matter seriously and have opened a comprehensive mission assurance investigation to review all facets of what occurred," USSS Chief Spokesman Anthony Guglielmi said in a statement.
"Any deviation from our protective protocols is unacceptable and if discovered, personnel will be held accountable," he added. "Modifications to the protective posture have also been made to ensure additional security layers are in place as we conduct this comprehensive review."
There were no signs of forced entry into the home. No arrests have been made.
A source with knowledge of the incident told Fox News the man appeared to be intoxicated and may have gone to the wrong house. The intrusion has sparked alarm in the White House, The Washington Post reported.
The agency tasked with protecting the president has expanded its roster of protective details in recent years.
Previously, national security advisers were provided Secret Service protection only when they traveled outside the Washington area, the news report said.
The incident at Sullivan's home came months after the husband of then-House Speaker Nancy Pelosi, D-California, was brutally attacked in the couple's San Francisco home.
