At least four shots were fired into the air early Tuesday just outside the G20 restricted traffic zone in downtown Toronto.

Police say that at about 3:30 a.m., ET more than a dozen off-duty RCMP officers witnessed the shots being fired by the occupants of a black sports car.

The car sped away from the scene, a parking lot in the King and Peter streets area. Police gave chase but lost the car somewhere in Etobicoke, in the city's west end.

They were able to get a partial licence plate number and are now looking for the vehicle.

They also found at least two shell casings near a club on Mercer Street, close to where the shots were fired.

Anti-G20 demonstrators, meanwhile, say they will be back in downtown Toronto on Tuesday trying to be heard.

Hundreds of protesters shut down traffic in parts of the city Monday, marching through the streets while officers on bicycles moved alongside, blocking side streets as they passed by.