PHILADELPHIA (AP) — Thousands of customers in downtown Philadelphia have lost power due to an underground transformer fire.

PECO officials said two underground transformers apparently blew at around 3 p.m. Tuesday. About 4,000 PECO customers in the area lost power.

Firefighters and PECO workers are currently at the scene. They're trying to determine exactly what happened.

Officials at Peirce College, which is located nearby, canceled classes for Tuesday afternoon and night due to the outages. All administrative offices at the school were also closed for the evening.