Heavily armed police secure the area after reports that a gunman fired shots at the Garden State Plaza mall in Paramus, New Jersey, Nov 4, 2013. A person with a gun opened fire on Monday evening in a New Jersey shopping mall shortly before closing time in the town of Paramus, and the mall was being evacuated, a county official said. [Photo/Agencies]

WASHINGTON - US authorities put a shopping mall in New Jersey on lockdown Monday night after shots were heard and a gunman was spotted, local media reported.

No casualties were reported so far.

The incident happened shortly before the Garden State Plaza Mall in Paramus, New Jersey, was to be closed for the night, CNN reported.

At least one gunman was said to have fired multiple shots at security cameras, the US broadcaster cited the state police as saying.

A police SWAT unit is responding to an "active shooter" at the Garden State Plaza, local WABC reported.

The mall has been evacuated, and the police have surrounded the mall searching for the gunman.