An explosion heavily damaged a church in upstate New York on Tuesday morning, leaving five people injured, New York State Police said.

Gas odor was reported inside the Abundant Life Fellowship Church in the town of Boonville, Oneida County, police said in a news release.

A firefighter was inside the church when the explosion occurred. The firefighter and a civilian were critically injured, according to police.

The five injured people have been taken to a local hospital for treatment.

Police are investigating the cause of the explosion. As of Tuesday afternoon, police said that there are no signs of any criminal activity involved in the explosion.