Utility crews ventured below the streets of downtown Atlanta on Tuesday to find what caused an explosion that sent manhole covers flying Monday night.

No one was injured when the underground explosion sent several manhole covers at least six feet into the air along Peachtree Street. But the exact cause wasn’t immediately known, according to an Atlanta fire captain.

The blasts temporarily shut down Peachtree Street between Mitchell and Alabama streets and Martin Luther King Jr. Drive between Pryor and Spring streets. Electricity was shut off to 10 nearby buildings. Power was restored to all the building by Tuesday night, Channel 2 Action News reported.

The explosion was thought to be electrical and related to underground repairs, Capt. Marian McDaniel told The Atlanta Journal-Constitution. Crews from Georgia Power and Atlanta Gas Light were at the scene trying to identify the cause, McDaniel said.

Georgia Power said cable inside an electrical fault caught fire and set off at least one explosion, Channel 2 reported.

MARTA rerouted buses away from the area during the investigation.