SAN DIEGO (CNS) - A power outage left thousands of homes and businesses in Balboa Park, Hillcrest, Golden Hill, Mission Hills and Old Town without electrical service late Thursday afternoon.

The blackout, which affected about 2,700 customers, began for unknown reasons shortly after 5 p.m., according to San Diego Gas & Electric.

Service was expected to be restored by about 8 p.m., the utility reported.

The cause of the outage was under investigation.