A series of explosions and a fire forced the evacuation of hundreds of people during Tuesday's afternoon rush hour in downtown St. Louis.

According to USA Today, electrical transformers exploded underneath the street right outside the US Bank Plaza building, causing a fire at 7th Street between Locust and Washington, just across from the St. Louis Convention Center.

The US Bank building, which is one of the largest structures in the city, was evacuated.

Firefighters closed off much of the surrounding area while they worked to control the fire. The St. Louis Post-Dispatch reports that the fire was quelled at about 6:30 p.m. CDT, but authorities remain on the scene to ensure safety.

The Associated Press indicated that utility company Ameren Missouri had to cut off electricity in the area where the initial blasts occurred, so firefighters could engage the blaze. The A.P. also reported fireballs and thick, black smoke rising from the hole near the edge of the US Bank building.

"Firefighters are applying water to the building in order to protect it from the heat," Capt. Dan Sutter of the St. Louis Fire Department told the Associated Press. The building itself has not been damaged.

Sutter also told the Post-Dispatch there are no reports of any injuries so far as a result of the incident, but that up to 10 people had to be rescued from elevators after power was cut from the US Bank building.

While the cause of the initial explosion is not yet known, the area has been under construction in recent months.