The collapse of a public heating system in one of China's coldest cities has left thousands of people without heat during a cold spell, state media reported on Thursday.

At least 10,000 families in Qiqihar City in northern Heilongjiang province, which borders Siberia, were affected by the breakdown and local authorities said it could take two days to fix, the official Xinhua news agency said.

The temperature dropped to 25 degrees below Celsius (-13 F) on Wednesday night, when the system feeding coal to the Qiqihar Thermal Power Co. broke down. The high on Thursday was minus 13 degrees Celsius (9 F).

The city distributed thousands of space heaters, hot-water bags and electric blankets to the chilled residents and fired up an additional 17 boilers to prevent a total plant failure.

Households in northern Chinese cities rely on public systems for heating, with their radiators typically fed by central coal-fired boilers that are turned on and off by local authorities at fixed dates.

The Xinhua report said heat was being restored to about three-quarters of the homes after emergency repairs.