TORONTO, Jan. 8 (Xinhua) -- Two adults and two children died of a house fire in Oshawa city of Canadian Ontario province Monday morning.

Around 8 a.m. Monday, the tragic event happened at a three-story rooming house in which some 11 people were living.

Oshawa Fire Chief Derrick Clark told a press conference Monday noon that the four people were pulled from various locations in the house and three other residents were taken to hospital with injuries.

Two men and a girl were pronounced dead at the scene while a boy was rushed to hospital where he later died of his injuries. Their identities haven't been released at this time. The relationships between the victims is still unclear.

It's unclear where the blaze started and if there were working smoke alarms, Clark said, noting the rear of the house seemed to suffer the most extensive damage.

A snowstorm hampered firefighters' efforts to contain the fire. Clark said the firefighers encountered "heavy fire and heavy smoke conditions."

An investigation of tragedy is under way.