Careless smoking is believed to be the cause of a fire that injured two people at a high-rise apartment building just east of Toronto's downtown core Thursday morning.

The small fire occurred inside a seventh-floor suite in a Toronto Community Housing Corp. building at Dundas and Sherbourne streets at about 5:20 a.m.

Toronto Fire Services District Chief James Green said the tenant was removed from the smoke-filled suite by the building's security officers.

Paramedics transported the tenant to hospital to be treated for minor burns and smoke inhalation, while one of the TCHC security officer was treated at the scene for smoke inhalation, Green told CP24 reporter Cam Woolley at the scene.

Firefighters rushed into the building and quickly extinguished the blaze, which Green said was confined to contents within the suite. They brought out a chair that caught fire and they used fans to clear smoke inside the building.

Green said the residents were told to shelter in place and remain inside the building.