Crews spent Thursday night sifting through rubble at a church in New London where the roof of the building collapsed hours earlier and began preparing for its anticipated demolition, as city officials say the historic structure is a total loss.

“We suffered a very serious setback here in downtown New London with the loss of one of the oldest and certainly one of the most gorgeous religious structures in the city,” New London Mayor Michael Passero said during a news conference Thursday evening. “The city was extremely fortunate in the manner of the collapse. It could have been a much bigger disaster for us, however, we did lose a cherished historic structure.”

Numerous emergency crews responded to 66 Union St. around 1:30 p.m. after the steeple of Engaging Heaven Church — which shares space with First Congregational Church — and the roof came down during a structural collapse, causing a thunderous roar and massive damage to the more than 200-year-old historic structure, according to Capt. Matthew Galante of the New London Police Department.

According to property records, the church was built in 1810 and had an office building added in 1975.

“Obviously nothing will be able to replace the hole now in our skyline by the loss of this building, but the city is resilient,” Passero said.

One woman was in the rear of the building at the time of the collapse and did not report any injuries, Galante said in a statement. Crews spent the evening hours Thursday rummaging through the rubble to confirm no one else was trapped.

Numerous police and fire departments and other agencies responded to provide mutual aid. This included the Urban Search and Rescue, Connecticut State Police K-9 Search Team, the state Department of Energy and Environmental Protection’s Emergency Response Unit and Connecticut Task Force 1.

The collapse closed several surrounding streets Thursday, including portions of State, Union and Masonic Streets. Nearby, Connecticut College students in the Manwaring Apartments building had to be evacuated and were informed they would not be able to return for a few days. They were relocated to a nearby hotel and received assistance from the American Red Cross.

Demolition was expected to begin Friday morning and start with the remaining two steeples, which were not considered safe in the wake of the collapse. What caused the collapse remains under investigation by the New London Fire Marshal with the assistance of the Office of the State Fire Marshal as well as state and local building officials, according to Passero.

“It will be some time before that determination is made,” the mayor said.

According to Passero, the building undergoes fire inspections but “there isn’t any routine building inspections.”

“We have not had time to determine if there was any recent inspection to the building structurally,” Passero said Thursday, adding that there was no indication by the congregation or the city that “there was anything wrong with this building.”

Anyone with information has been encouraged to contact the New London Fire Marshal’s Office at 860-447-5294 or the New London Police Department Detective Division at 860-447-1481. Anonymous information can be sent via text message to Tip411 (847411).