An explosion took place in a building of the Harvard Medical School in Boston early Saturday, the school’s police department said, in what authorities described as an intentional act.

Two people were seen fleeing the building when a police officer from the Harvard University Police Department arrived at the scene, according to the police statement.

The university released still images from video surveillance of the two individuals Saturday afternoon, asking for the public’s assistance in identifying them.

The episode unfolded at 2:48 a.m. in the Goldenson building of the medical school, where an officer from the Harvard police department was dispatched after a fire alarm was activated, Steven G. Catalano, a spokesperson for the university police, said in a statement.

An officer who arrived at the scene saw the individuals running from the building, Catalano said. The arson unit of the Boston Fire Department determined that the explosion was “intentional,” he said.

— The New York Times