Officials evacuated the building as a precaution after the incident. No injuries were reported.
About an hour and a half later, British transport police responded to reports of a suspicious package in the mailroom at the Waterloo Station, a major rail and London Underground hub. Around 12:10 p.m. local time, authorities were called to investigate a third suspicious package reported at the offices of City Aviation House, near London’s City Airport. Neither package was opened, and no injuries were reported.
No arrests have been made in connection to the devices and no one has claimed credit for them. Authorities continue to investigate.
The official terrorism threat level throughout Britain is set at “severe,” indicating that intelligence analysts believe an attack is highly likely.
The Associated Press contributed to this report.