Fire officials say a raging fire that has damaged the Serbian Orthodox Cathedral of St. Sava in Midtown Manhattan has been deemed suspicious for now, though the investigation is continuing.

The fire started at about 7 p.m. Sunday, just hours after its Orthodox worshippers celebrated Easter, and sent plumes of smoke billowing into the city's skyline.

"We had a very heavy volume of fire on arrival, which is always a concern," said Deputy Assistant Fire Chief Mike Gala at the scene. "We deemed the fire suspicious."

The blaze was largely extinguished three hours later, but firefighters had to beat back small pockets of flames. The fire gutted the building and destroyed the church's roof and stained glass.

Fire officials said the church's caretaker ran inside the Gothic Revival style building to try to put out the blaze but suffered minor smoke inhalation and had to be rescued.

The fire broke out on the same day Orthodox Christians around the world celebrated Easter. The church website listed services on Sunday morning and an Easter luncheon at 1 p.m.

Alex Velic, 31, the caretaker's stepson, told the Daily News he lives next door. He said he smelled smoke and came outside and saw the church on fire.

"Once the fire caught the wood there was flames coming out of the top of the church. That's when people were going crazy," Velic said, according to the newspaper. "I'm in shock. I don't know what to say. It's sad."

Father Djokan Majstorovic, the church's priest, struggled to get to the fire scene blocked off by firefighters.

"I feel like I'm in a nightmare right now," he said.

City Council Member Corey Johnson has called for a full investigation into the cause of the fire.

"This is a huge loss for the community," he said. "In addition to being a place of worship, this historic building was a New York City landmark, treasured by the people" living in the neighborhood.

The church was designed by architect Richard M. Upjohn and was built in the early 1850s. One of its earlier congregants was novelist Edith Wharton, who wrote "The Age of Innocence." She was married in the church in 1885.

The Serbian Orthodox Church purchased the building from the Episcopal Diocese in New York in 1943. The building was designated a city landmark in 1968.