Updated 11:20 p.m.

A package exploded on the campus of Northeastern University in Boston late Tuesday, injuring one staff member. Boston police superintendent Felipe Colon said Tuesday night that a second package was “ultimately rendered safe” by the bomb squad.

He added that the scene was secure and that it was an ongoing investigation.

The Boston Regional Intelligence Center is working with the FBI and the Joint Terrorism Task Force to look into the incident, Boston Police Commissioner Michael Cox said Tuesday night.

“We are going to be working and continue to work with all our campus security partners as well to make sure all the students here are safe, as well as the rest of the residents in the city,” Cox said. “We advise, you know, any folks out there that might, you know, see something, say something — and let us know and dial 911 so that we can ensure and follow up on any of those things.”

More details on the explosion, such as how the packages arrived on campus, were not yet available.

“As a mom, I just sent my own two little babies back to school in our Boston public schools,” Mayor Michelle Wu said at the press conference Tuesday night. “I take very seriously that this city is home to everyone's young people, from our littlest learners up to our college students and university staff. And so we want to make sure to emphasize that this is of the utmost priority, the safety and well-being of all of our young people here. Again, very, very grateful to everyone who has been responsive and part of this action tonight.”

NBC Boston reported that the package that exploded went off as it was being opened near the university's Holmes Hall, which is home to the university's creative writing program.

Police converged on the campus shortly before 7:30 p.m., and the university asked students who had gathered for an evening journalism class at the hall to evacuate the building. Colon confirmed in a 10:30 p.m. press conference that a 45-year-old male staff member suffered minor injuries to his hand.

“We’re monitoring the situation at Northeastern and we’re ready to work with the university and our law enforcement partners on any prosecutions that may develop. The quick and thorough response by Boston Police and other agencies is the start of a comprehensive investigation to determine exactly what occurred here.”

Harvard University and the Massachusetts Institute of Technology, both on the other side of the Charles River separating Boston from Cambridge, said they were increasing patrols on their campuses as a precaution and urging students and faculty to report anything suspicious.

Mary Blake contributed reporting.