The FBI is investigating after an "intentional" explosion inside a building on Harvard University's Longwood medical school campus early Saturday.

Harvard officials told Fox News Digital that just after 2:45 a.m., a Harvard University Police Department (HUPD) officer was dispatched to the Goldenson building at 220 Longwood Avenue in Boston for a fire alarm activation.

When the officer arrived, they saw two people fleeing the building , officials said.

FBI PITTSBURGH FIELD OFFICE TARGETED BY DRIVER IN 'ACT OF TERROR,' OFFICIAL SAYS

The officer tried to stop the pair before proceeding to the fourth floor where the alarm was triggered, finding an explosion had occurred.

Harvard University Police Department released photos of the two suspects wearing masks and head coverings.

See Full Page