Authorities are investigating an “intentional” explosion that shook Harvard University’s Longwood Medical School campus on Saturday, prompting emergency responses and heightened security measures.

The incident occurred around 2:45 a.m., triggering a fire alarm and drawing the attention of Harvard University Police Department (HUPD) officers. According to reports, two individuals fled the building upon the officer’s arrival, though they managed to evade capture before the officer entered the premises to assess the situation.

Boston police released surveillance footage on Saturday depicting two suspects wearing masks and hooded sweatshirts. The Boston Fire Department confirmed the explosion was deliberate but found no additional devices during a building sweep. Sources familiar with the investigation told the New York Post that the explosive device was not classified as a bomb, though details remain undisclosed.

Harvard officials stated the university police are cooperating with local, state, and federal authorities, including the FBI, which is assisting in the probe. The incident adds to a year of tension for Harvard’s community, following high-stakes negotiations with the White House over federal funding and legal disputes.

No casualties or injuries have been reported at this time.