A crowd of Harvard University graduates had their annual Senior Sunrise celebration on the Weeks Footbridge cut short Friday morning after police cleared the area.

Photos from the scene, shared by NBC Boston, showed a large crowd of students gathered on the pedestrian bridge over the Charles River as police officers from multiple agencies responded.

In an email to Boston.com, Massachusetts State Police said troopers were called to the bridge shortly after 5 a.m. after receiving reports that a large group of people was blocking the pathway and attempting to swim in the Charles River.

“Shortly after 5 a.m., Troopers from the Boston barracks responded to reports of a large group of people blocking the path of the Weeks Footbridge in Cambridge and attempting to go swimming in the Charles River,” a State Police spokesperson said.

Swimming in the Charles River is generally prohibited except for certain sanctioned events, according to the Department of Conservation and Recreation.

Cambridge police and Harvard University Police also responded to help clear the bridge.

The gathering was part of the annual Senior Sunrise event for Harvard’s graduating Class of 2026, a tradition in which seniors gather before dawn to watch the sunrise together as they embark on life after graduation.

It was not immediately clear whether any arrests, citations, or injuries were reported. 

Cambridge police referred questions about the incident to State Police and Harvard University Police. A spokesperson for Harvard University Police did not immediately respond to a request for comment.

The gathering came one day after Harvard’s Class of 2026 celebrated commencement, where comedian and alumnus Conan O’Brien delivered the keynote address.