This heart-breaking footage shows rescuers searching for any surviving children beneath the rubble of a collapsed school gym roof that killed three pupils and left two injured.

Seven middle schoolers were reportedly playing basketball at the gym in Jiamusi, in China's northernmost Heilongjiang Province, on the evening of November 6, when the roof suddenly caved in.

Three of the four children trapped by the collapse died. Two more were injured and taken to a nearby hospital with non-life-threatening injuries.

Local residents and firefighters rushed to the scene to search for survivors. Video footage shows them trying to navigate through piles of debris and thick snow. At the end of the clip, several of them are seen pulling one person who appears to be unconscious away from the wreckage.

Meanwhile, police reportedly detained the collapsed building's owner.

Local officials speculated the incident might have been caused by the heavy snow.

The Jiamusi Meteorological Observatory had previously issued a red alert for heavy snowfall and urged local businesses to close 'if necessary.'

In a statement released on Monday at 5:30 pm local time, the Observatory said: 'Our city has accumulated 15 millimetres of snowfall in the past six hours, and snowfall will continue until the morning of the 7th. The total accumulated snowfall during this period may reach 25-35 millimetres. Please be vigilant.'

However, local media reported that the gym had been open despite the warnings.

A similar tragedy occurred just months ago, when the roof of a middle school in Qiqihar collapsed, leading to the deaths of eleven individuals, including several members of a girls volleyball team. Officials said it had been caused by a construction company storing highly absorbent materials on the roof. The investigation is ongoing.