The Mission of Iraq, which sits on a wealthy Upper East Side block near Central Park, has a dark secret: Its basement was used as a jail equipped for torture under Saddam Hussein’s regime, The Post has learned.

When he rose to power in 1979, the despot had the terrifying “detention room” installed inside the five-story building at 14 E. 79th St. — right across from billionaire former Mayor Michael Bloomberg’s home, according to two Iraqi officials speaking on the condition of anonymity. MORE