PHOENIX - An explosion at a building near Metro Center Mall shattered the first-floor windows of the building, according to the Phoenix Fire Department.

About 50 people were inside the Corporate Center building near 10000 N. 25th Drive at the time, but there were no injuries reported.

One man, who was inside the building during the explosion, shared his experience only with 12 News.

"All of a sudden, the lights started flickering," said Timothy. "Then there was an explosion."

It didn't take long for Timothy and his co-workers to know something was very wrong.

"Ten seconds later, the smoke alarm started going off," he said, and everyone scrambled to get out.

A witness said there were flames and smoke shooting up from the basement, but Phoenix fire officials say there was no fire as of 10:45 a.m. and the situation was stabilized by Glendale and Phoenix fire crews.

The explosion took place in an underground electrical vault, said Cpt. Ron Jesse of the Phoenix Fire Department.

At least 15 fire units responded to the scene. APS turned off service to the complex while crews were there. It was not clear how soon people could re-enter the building.