The two suspects with their faces covered entered the Bombay Bhel restaurant late on Thursday night, dropped the improvised explosive device and fled, police said.
The restaurant is in Mississauga, about 28 km from here. Prime Minister Justin Trudeau expressed his concern over the incident on Twitter.
'We're in solidarity with the victims of this violence, and wish a swift recovery to the injured. We're working closely with police and officials in Mississauga on this,' Trudeau said in a tweet.
Peel Regional Police Chief Jennifer Evans has said that there is no indication that the explosion was an act of terrorism or hate crime.
"There is no indication that this is a terrorism act. There is no indication that this is a hate crime at this time. We haven't ruled anything out as we start our investigation," Evans was quoted as saying by the Canadian broadcaster CBC.
The focus of police is now on finding the two men and identifying just what motivated the attack while two separate private parties were underway, the report said.
"I want to assure everyone that every police resource is being used to locate the people responsible for this horrendous act," Evans said.
A 35-year-old Brampton man, a 48-year-old Mississauga woman and a 62-year-old Mississauga woman suffered critical injuries and were rushed to a Toronto trauma centre, according to Peel Region paramedics.
All three have since been released from hospital, the report said.
The remaining 12 victims who were treated for minor injuries ranged in age from 23 to 69, police said.
Approximately 40 people were inside at the time, including several children under age 10, it said, adding that no children were hurt.
Meanwhile, Mississauga Mayor Bonnie Crombie extended her sympathies to the victims, saying she was thankful there were no fatalities as a result of the 'heinous' crime.
'This is certainly not anything you would expect to happen in Mississauga, not my Mississauga. This is not the Mississauga I know,' she was quoted as saying in the report.
Peel Regional Police said they received a call about the incident at 10.32 pm (local time on Thursday), (0800 IST yesterday). Mississauga is Canada's sixth largest city.
In New Delhi, External Affairs Minister Sushma Swaraj had said that Indian missions in Canada are working round the clock after the blast.
Police has issued CCTV footage of the two suspects.
"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.
"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," police said. -- PTI
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