Two arrests have been made after a mass shooting on Sunday night at a mosque in Quebec City, Canada, that killed six people and wounded several more, said a report.

Court officials in Quebec City identified the suspects as Alexandre Bissonnette and Mohamed El Khadir. They were to be arraigned Monday afternoon, according to Globe and Mail.

Police descended on homes and other sites around Quebec City hunting for information in what they described as a large and ongoing investigation. They said surveillance of mosques around Quebec has been stepped up.

Many of the witnesses spent the night at a sports centre near the mosque where they were questioned.

Condemning the 'terrorist attack', Prime Minister Justin Trudeau said: "Canadian law enforcement agencies will protect the rights of all Canadians, and will make every effort to apprehend the perpetrators of this act and all acts of intolerance."

Of those taken to hospital, five were still in critical condition after being operated on overnight, hospital officials said Monday morning. Twelve others with minor injuries have been treated and released, said the report.

Investigators do not believe any suspects beyond the two men in custody remain at large and they would not comment on identity of the attackers, motives or methods, it added.