Northeastern China's biggest city of Harbin has been pummelled by its worst snowstorm for 50 years, state media said Tuesday.

More than 50,000 people were mobilised to clear snow in the city, the capital of Heilongjiang province, the official news agency Xinhua reported.

It cited city authorities as saying the snow was the worst since they first began recording daily weather conditions in 1961.

The storm has claimed the lives of at least four people and injured another seven in neighbouring Jilin province, Xinhua added.

Schools in both provinces were shut on Monday and Tuesday and flights and trains delayed as snow blanketed the area for a third day.

The blizzard comes less than a month after a choking smog in the region shuttered schools, roads and airports for two days.