FULLERTON (CBS) — Two fraternity brothers were stabbed early Friday morning at a Cinco de Mayo party near the Cal State Fullerton campus.

A fight broke out around 1:30 a.m. when six to eight men who showed up to the party were not allowed inside the Phi Sigma Kappa fraternity house, according to Sgt. Andrew Goodrich of the Fullerton Police Department.

The two victims, a current student and a university alumnus, were stabbed in their backs. One of them suffered a collapsed lung and was expected to undergo surgery, according to CBS2’s Kristine Lazar.

The suspects, who fled the scene, were described as African American.

No other details were immediately released.