NEW HAVEN, Conn. (AP) — New Haven's mayor says authorities have found evidence that an incendiary device or material was used to start a weekend fire at a mosque in the city.

Federal, state and local authorities are investigating Sunday afternoon's blaze that damaged two floors of the Diyanet Mosque as arson.

Mayor Toni Harp in a statement issued Tuesday says if it's proven the fire was intentionally set, the city will "bring all resources to bear to bring in those responsible for the attack." She did not detail what the incendiary device was.

Authorities have offered a $2,500 reward for information leading to an arrest.

The Muslim Coalition of Connecticut has set up an online fundraising page to help with mosque repairs, which had just under $57,000 in pledges as of noon Tuesday.