One man has died and four others were seriously injured following a string of shootings across the city overnight, Toronto police say.

The first shooting occurred at around 2:30 a.m. in the city's downtown core.

Two people, believed to be in their 20s, were taken to hospital in serious condition after investigators say gunfire erupted outside a house party on Niagara St. west of Bathurst Street.

According to investigators, a female was shot in the leg and a bullet grazed a male victim's head. Police added that several drivers and pedestrians narrowly missed being hit by gunfire and cars and cabs in the area were found riddled with bullet holes.

"There were several people in the street and so it is quite concerning and fortunately not more people were injured," Const. Allyson Douglas-Cook told CP24 at police headquarters on Sunday afternoon.

Multiple people were arrested near the shooting scene Sunday morning in connection with a stolen vehicle investigation but police could not say if the two incidents are connected.

Police are also trying to determine if an injured person found near Bathurst and Dupont streets this morning was wounded in the Niagara Street shooting. It is unclear if the victim in this case was stabbed or shot, Cook said.

Two suspects sought in connection with East York shooting

About an hour after the first shooting in the downtown core, more gunfire was reported in East York.

The second shooting occurred at around 3:30 a.m. on Wakunda Place, near O'Connor Drive and Victoria Park Avenue.

Police say a man believed to be in his mid-20s was taken to hospital in non-life-threatening condition after the incident, which investigators say took place outside on the street.

Suspect information is limited but police say investigators are searching for two suspects in connection with the case.

Fatal shooting in Scarborough

The violence continued Sunday morning as more gunfire rang out in Scarborough.

At around 4:30 a.m., paramedics were called a beauty salon in the area of Ellesmere and McCowan roads and found a man in the basement of the building without vital signs.

Police say the victim, who is believed to be in his mid-20s, was rushed to hospital suffering from multiple gunshot wounds but was pronounced dead a short time later.

Cook said witness reports indicate that a gathering was taking place at the salon at the time of the shooting.

"What happened and what resulted in someone losing their life, we don't know," she added.

Homicide detectives remain at the scene and  no suspect information has been released.

When asked about the series of violent incidents in the city overnight, Cook called the shootings "concerning."

"We are going to do everything we can to try and get some answers and try to find the people who are responsible for this," Cook concluded.