A normally quiet summer session at the University of San Francisco was interrupted Tuesday morning by a campus assault and robbery, university police said.

Two students at the University Center were injured when suspects punched them in the face and stole their belongings, police said. Emergency crews treated the victims for bloody noses.

In a crime bulletin sent by email Wednesday, USF police said two men and one woman entered the center, where students were studying. One of the men acted as a lookout while the woman attacked the two students.

A witness said he saw the aftermath, with police aiding one of the two victims outside the university center.

"All I heard was there was blood on the floor," Derrick Bonilla said, adding that the victim seemed dazed and distraught.

Police said it's an unusual occurrence.

"This is normally a very safe atmosphere for students, whether studying or socializing," said Kevin Dillon of the USF Department of Public Safety. "This is very random."

Most buildings on the campus require a secure ID card entry, but police said the suspects also stole a laptop from another building before the assault.

Student Ana Molina said she's relieved the University Center is one of the only public buildings on campus, but she felt bad for the victims.

"I think it's very disturbing they had to be treated for wounds," she said.

The three suspects were last seen running off campus onto Fulton Street, police said. The university said the suspects were captured on surveillance video that's been handed over to the police.