Updated

An explosion rocked the city of Sun Prairie, Wis., on Tuesday after a contractor struck a natural gas main, leveling buildings and injuring at least two firefighters and one police officer, authorities said.

No deaths were immediately reported, said Lt. Kevin Konopacki of the Sun Prairie Police Department. The firefighters were rushed to a hospital, while the officer and some residents were treated at the scene.

Multiple buildings around Main Street, an area filled with bars, restaurants and other businesses, were leveled, Madison's WISC-TV reported, citing police.

Firefighters and police responded to a reported gas leak in the city’s downtown area around 6:20 p.m., before the explosion, authorities said. They were evacuating a five-block radius when the explosion occurred, likely saving lives.

WE Energies spokeswoman Cathy Schulze said the gas main strike was reported to the utility ahead of the blast, and first responders were working to shut off the gas to secure the area.

Contractors had apparently punctured a 4-inch main that sent natural gas leaking into a building, WE Energies spokeswoman Amy Jahns said.

The blast was reported around 7:15 p.m., and appeared to be centered on the Barr House, a local pub. Video posted to social media shows fires blazing with smoke billowing toward the sky amid a heavy police presence.

Firefighters were battling flames for more than three hours after the blast, Konpacki said. The buildings would be searched once the fires were out.

An employee of Madison's WMTV-TV said his "whole house shook" from the explosion.

Steve Owen, 60, a small business owner, said he saw firefighters and police on the street just before the explosion. He said he saw a ball of fire as the building across the street “literally lifted up.”

"People were scrambling," Owen said.

The Red Cross of Wisconsin tweeted that its personenel have set up a reception center for displaced residents at a local middle school.

Authorities were still working late into the evening to determine when residents could return to their homes.

The Associated Press contributed to this report.