FDNY spokesman Jim Long told the Daily News Monday night that the matter was under investigation. He declined further comment.
The newspaper says the stenciled picture of the president with the word "believe'' and then defaced with the word "hustler'' in big red letters was discovered at Engine 45, Ladder 58 in East Tremont.
Beneath the image, someone scrawled the words, "Allah Akbar,'' or "God is great'' in black ink.
A police sketch of the Unabomber appears on an adjacent panel.
Lt. Kenneth Durante refused on Monday to comment about the images at the firehouse.
FDNY rules bar firefighters from displaying vulgar or offensive material in the firehouse.