Absolute mayhem in Manhattan ... there was an active shooter who injured multiple people before turning the gun on himself.
The New York Police Department tells TMZ ... officers got a call for shots fired Monday at 345 Park Avenue.
There are reports that one of the gunshot victims is a police officer and that the suspect was found dead from an apparent self inflicted gunshot wound.
Videos on social media show a massive police response ... cops are running towards the shooter and civilians are running for cover.