ROCKFORD, Ill. — A lightning strike caused a roof fire Monday that severely damaged a historic Catholic church in Rockford, Illinois, and left three firefighters injured, authorities said.

The Rockford Fire Department determined that lightning set the roof on fire, Mike Rotolo, the department's fire prevention coordinator, told CNA Tuesday. The damage to the church may exceed $3 million, he said.

A yellow sign with the message “Condemned: Do Not Enter” was posted outside the church Monday, he said. Rotolo said this means that the building is not safe to use in its current condition.

The church is located outside the Chicago metropolitan area in the far northern part of the state. The church was first blessed in 1853, according to the parish’s website.

In a statement, the Diocese of Rockford said the fire broke out before 7 a.m. on Aug. 8. The diocese posted a video on its Facebook page showing firefighters responding to the blaze.

No one was inside the church during the time of the fire and the pastor safely removed the Holy Eucharist from the building, the diocese said.

Three firefighters responding to the scene suffered non-life-threatening injuries, the fire department said in a tweet.

#UPDATE. 400 North 2nd Street. 3 firefighters were injured in two separate Maydays. All are currently being evaluated at local hospitals with non-life threatening injuries. pic.twitter.com/oNdcyGIZdG

— Rockford Fire (@RockfordFire) August 8, 2022

“Bishop David Malloy extends his profound gratitude to all the first responders, the vigilant neighbors, and all those around the diocese who have offered prayers during this extremely sad and unfortunate event,” the diocese’s statement said.

“Prayers are also being offered for those three courageous firefighters reported to have sustained injuries while fighting this fire,” the statement added.