CALIFORNIA, Pa.—Officials say California University of Pennsylvania was placed on lockdown Wednesday after an armed robbery, but a suspect has been arrested.

An alert was issued just before noon after an armed robber was reported in Residence Hall B. Authorities say an unidentified suspect was arrested about 20 minutes later, and no injuries were reported.

The state school has about 8,600 undergraduate and graduate students, and is about 35 miles south of Pittsburgh.