Prime Minister Justin Trudeau has offered his condolences to victims' families following Sunday's mass shooting at a condo in Vaughan, Ont.

"Obviously, my heart is breaking for families of the victims, for people who are injured in the hospital still," Trudeau told CTV National News Chief News Anchor and Senior Editor Omar Sachedina on Monday. "It’s something that is unthinkable. I can't imagine what they're going through."

On Sunday night, five victims and a suspect were killed after a mass shooting at condominium in Vaughan, near Toronto. Three of the victims were members of the building's condo board, and multiple residents have told CP24 the suspect was involved in a dispute with the board.

A sixth victim survived the shooting and is currently in hospital. The suspect was shot to death at the scene by police.

"Obviously, we're expecting police to conduct full investigations," Trudeau said. "We're giving any support that [they] need from the federal side for that. But I think it's also important that we take a moment to recognize the first responders who rushed into danger, who were there to keep people safe in a very, very difficult situation."

Authorities say the 73-year-old suspect was armed with a semiautomatic handgun. It is not yet known if the weapon was acquired legally. The investigation remains in its early stages.

Trudeau's government has proposed new gun control legislation that would largely freeze the sale, purchase or transfer of handguns in Canada, as well as enshrine in law a definition for "assault-style" weapons.

Asked if the proposed legislation could have stopped Sunday's shooting, Trudeau noted more needs to be known about the circumstances of the shooting before considering whether updated federal gun control policy could potentially have made a difference.

"We've certainly strengthened gun control in this country, but we need to do more to keep Canadians safe and we're committed to doing that,” Trudeau said on Monday.