SAN DIEGO – Authorities say an electrical transformer exploded underground outside Petco Park Saturday evening, knocking out power in parts of the busy Gaslamp Quarter just as a sold-out game ended.

A call came in around 9 p.m. Saturday reporting that a transformer had blown underground in the area of 7th Avenue and K Street, according to the San Diego Police Department. Authorities shut down 7th Avenue and L Street, 6th Avenue and K Street, and 4th Avenue and Market Street.

The closure snarled traffic as tens of thousands of people poured out of Petco Park and joined the usual crowds of weekend nightlife. Some people got stranded in elevators and others waited hours in parking garages, viewers and officials at the scene told FOX 5.

Police and firefighters directed traffic and helped anyone who was stuck while utility crews tried to restore power to surrounding homes and businesses. The San Diego Marriott Gaslamp Quarter, located right in front of the underground transformer, lost power until generators kicked back on, the hotel’s general manager said.

FOX 5’s Jason Sloss spoke with a representative with San Diego Fire-Rescue who said Marriott employees originally reported a structure fire outside, which turned out to be flames coming from a manhole covering the site where the transformer exploded. He said there were no reports of injuries.

According to SDG&E, more than 1,100 customers lost power across Center City, Balboa Park, Golden Hills, Logan Heights, Mountain View and Lincoln Park. By Saturday morning, no outages were reported in the area.

Officials did not immediately say what caused the transformer to explode.

FOX 5’s Matt Meyer contributed to this report.