Gov. Kathy Hochul on Sunday announced an immediate "burn ban" for all of Long Island and New York City, and for parts of the Hudson Valley. The ban prohibits igniting any outdoor fires to remove brush or debris, as well any uncontained campfires or open fires for cooking.

Law enforcement agencies are still interviewing all 911 callers to rule out any possibilities, but they "strongly feel that it was accidental."

The current "operating theory" is that the fires were sparked accidentally in a backyard near Sunrise Highway, authorities said on Monday.