The high-rise fatal fire in Tianjin that killed 10 and injured five others on Friday was caused by piles of sundries and discarded decoration materials in the elevator on the 38th floor of the apartment building, an investigation team said on Sunday.

The fire, which broke out on the 38th floor in the city's Hexi district, quickly expanded, as construction enterprises had privately drained stored water for firefighting, the team explained, adding the builders also had illegal accommodations there.

Eleven suspects, including seven from a Tianjin enterprise, have been criminally detained for alleged heavy liability related to the fire, the team said.

Investigations are still underway.

The fire broke out at 4:07 am Friday and was extinguished at 6:40 am. More than 200 firefighters and 34 fire engines were sent to the scene.

Firefighters said an area of about 300 square meters was damaged.

Sun Wenkui, vice-mayor of Tianjin, said during a late news conference that day that Tianjin would conduct inspections across the city, particularly on high-rises and construction sites, to eliminate potential fire risks.