Two people are dead and two others are seriously injured after a gunman opened fire at a cafe north of Toronto.

"The information that we have is that a man arrived here and began shooting," York Regional Police Const. Andy Pattenden said Wednesday morning.

Police have not released any information on the victims or possible suspects. It is not yet known if the victims were employees or customers at the cafe, nor if other people were inside.

Officers are looking for witnesses and video surveillance of the shooting.