A weekend fire at a New Haven, Connecticut, mosque that caused significant damage was intentionally set, the city’s fire chief said Monday.

"We've detected that there is intent in this fire," New Haven Fire Chief John Alston said. “This was intentionally set."

The fire at the Diyanet Mosque was reported around 4 p.m. Sunday, according to NBC Connecticut, and caused considerable damage to the first and second floors. There were no injuries, but one man was in the mosque at the time of the fire.

The fire broke out on the first day of Ramadan.

No arrests have been made, but Connecticut Gov. Ned Lamont said that his office would be working with law enforcement to ensure that those responsible are held accountable.

Lamont tweeted that "a hate-fueled attack on a religious institution — any religion — is disgusting and appalling. There is no place for it in our state or our nation."

A $2,500 reward for information is being offered, and the Connecticut chapter of the Council on American-Islamic Relations also said it was offering a $10,000 reward for information leading to the arrest of the person or people responsible.

The federal bureau of Alcohol, Tobacco, Firearms and Explosives and the FBI are assisting in the investigation, NBC Connecticut reported.

"We are working with our federal and state partners to make sure that there is no underlying issue … to the greater religious community,” New Haven interim Police Chief Otoniel Reyes said Monday.

The governor said targeting a religious site is particularly hateful. “I find an attack like this is especially hurtful and hateful when you attack an institution for what people believe,” he said at a news conference Monday.

Lamont said the mosque's imam told him that churches and synagogues have offered to help. "They welcome the help, but they want to worship right here in this place," the governor said. “And we’re going to do everything we can to make that possible."

The building is uninhabitable, the fire chief said, but some artifacts have been recovered and turned over to the imam, according to NBC Connecticut.

"In this time of their season of religious worship, our hearts go out to them," Alston said.

NBC Connecticut reported that the fire broke out in an area that was under construction.

"Everyone was hoping when it was being finished, want to see how it looked, excited. It was very nice for the community," Telat Bozan, of West Haven, told the station.