Two unidentified men detonated a powerful improvised explosive device at an Indian restaurant in Canada's Ontario province, injuring at least 15 people, police said today.

Three of them have suffered "critical blast injuries" and were rushed to a Toronto trauma centre, Canadian broadcaster CBC reported.

Police said that the incident occurred at 'Bombay Bhel' restaurant in Mississauga, about 28 kms from here.

Peel Regional Police said they received a call about the incident at 10:32 PM (local time yesterday), (0800 IST today).

Mississauga is Canada's sixth largest city.

Health officials have rushed 15 patients to hospitals, the police said.

Police said that two suspects detonated the improvised explosive device in the restaurant and fled.

"Two parties fled the scene immediately after the incident. First described as male, 5'10-6feet, stocky build, mid-20s, light skin, wearing dark blue jeans, dark zip up hoodie pulled over head, baseball cap with light grey peak, face covered with black cloth material," Peel Regional Police said in a tweet.

"Second male described as 5'9"-5'10", fair skin, thin build, faded blue jeans, dark zip-up hoodie hood pulled over head, grey t-shirt, dark coloured skate shoes, face covered. Looking for public's assistance in identifying the parties that fled following the explosion," it said in another tweet.

Police have issued CCTV footage of the two suspects.

It was not immediately known as how many people were inside the restaurant when the incident took place.

The motive for the attack was being investigated.

The shopping plaza in which the explosion took place has been sealed off, Peel Regional Police said in a tweet.