The film explores the street violence in Chicago, Illinois, and Lee decided to use the launch to further raise awareness about the mounting death toll in the city by hosting a protest with moviegoers and civil rights activist Al Sharpton in Manhattan.

The premiere came a night before the city's police superintendent was fired over the killing of Laquan MCDonald last year (14) by a police officer now indicted for murder.

Lee predicted the superintendent "is not going to be the only one" to lose his job and his leading man, John Cusack, called the officials' decision to withhold the tape "unacceptable", and claimed the recording was kept under wraps until the election year in his native Chicago was over.

"It's very tragic that information was suppressed for an election cycle," he said.