Toronto police are calling for permanent video surveillance cameras to be installed in the downtown core after a violent weekend.

According to Staff Sgt. Shaun Narine, there can be as many as 50 fights on a weekend night in the downtown area dubbed the entertainment district.

"Because they know right now they can get involved in something with a crowd of between 10,000 and 100,000 people," Narine said at a press conference.

"It's very easy to disappear in the crowd."

Three people and one Toronto police officer were sent to hospital suffering from stab wounds after a fight broke out in the city's nightclub district Sunday morning.

Two men in their early 20s have been charged in connection with the stabbings.

A man reportedly was wielding a knife and had started stabbing people in a John and Pearl Streets parking lot.

The officer chased and arrested the suspect. In the process, the officer received wounds to his neck and arm.

One of the stabbing victims suffered serious injuries. The other three victims sustained only minor wounds.

Sunday's incident is the second night of violence in Toronto's nightclub district in as many days.

A shooting early Saturday morning sent one person to hospital in critical condition and three others with gunshot wounds.

Police continue to probe Saturday's shooting. Investigators ask anyone with information to call police at (416) 808-7000 or Crime Stoppers at 1 (800) 222-TIPS (8477).