Video: Manhole cover thrown into air by underground fire.

PROVIDENCE, R.I. (WPRI) — Buildings were evacuated and streets blocked off in downtown Providence, Rhode Island, on Wednesday amid an underground fire that caused a manhole cover to explode into the air.

Anthony Knasas told Nexstar's WPRI that he was in an alleyway, taking a picture of a mural, when a manhole cover erupted into the air just a few feet away from him.

The moment was caught on video, which you can see in the player above. In it, Knasas can be seen taking a photo as the manhole cover behind him is thrown into the air and flames rise from the hole.

Knasas explained that the alleyway had started to fill with smoke, followed by a "giant boom."

"It sounded bad, it sounded like some sort of explosion," he said, adding that he had no idea the "flame ball" was right next to him.

While a city spokesperson told WPRI it was determined that a "small underground electrical fire" caused the manhole cover to become dislodged around 2 p.m., it's unclear what caused the fire itself.

Emergency crews were still on the scene in downtown Providence into the afternoon. Some buildings had been evacuated as a precaution, but the city spokesperson said there was no immediate danger to the public.