Harvard Medical School officials say an explosion on campus was intentional and reported seeing two people run from the building; the school has asked the public to help identify the individuals captured on surveillance video. School leaders characterized the incident as an intentional act and are coordinating with law enforcement as they assess damage and campus safety implications. The school has warned the community about potential disruptions to research facilities and clinical operations located in or adjacent to the impacted building, and investigators are reviewing surveillance footage and access logs to determine motive and next steps for restoring normal campus functions.