US Secret Service investigating break-in at National Security Adviser Jake Sullivan's home

Protection detail were unaware of the intrusion until the top White House official alerted them, media outlets reported

White House National Security Adviser Jake Sullivan. AP

The US Secret Service is investigating how an unknown man was able to break into National Security Adviser Jake Sullivan's home in Washington last month.

The door to Mr Sullivan's home was unlocked and the intruder entered about 3am, the Associated Press reported. Mr Sullivan, who has a round-the-clock Secret Service protection detail, was unharmed in the incident.

Mr Sullivan confronted the individual and later told investigators he believed the intruder was intoxicated, CNN reported. Agents stationed outside the White House official's home were unaware of the intrusion until the man had left the property.

Anyone who intrudes on property of those under Secret Service protection are typically detained and questioned, although in this case the man reportedly left the property before Mr Sullivan's detail was alerted. Mr Sullivan informed Secret Service of the intrusion after the intruder had already left.

The incident was first reported by The Washington Post.

Secret Service spokesman Anthony Guglielmi told the Post that the Secret Service has placed additional security precautions around Mr Sullivan's home.

Mr Guglielmi said that the Secret Service is “taking this matter seriously”. He added that any deviation from protocol was unacceptable.