Montreal: Two people were shot dead after a violent argument erupted among customers queueing at a McDonald's restaurant in Toronto, Canadian police said Saturday.

Two men aged 40 and 25 were killed after an altercation with an armed security guard visiting the restaurant to get food, police said.

The security guard suffered a wound to a hand and was hospitalized following the incident.

Police were scrutinizing security camera footage of the incident as they sought to understand how the argument escalated into violence, a spokesman said.

Around 20 people were in the restaurant when the shooting occurred at around 3 a.m. local time (0800 GMT), police said.