CHONGQING -- Chinese President Hu Jintao and Premier Wen Jiabao have ordered the local authorities to spare no efforts to save those people buried in a fatal landslide in the southwest city of Chongqing.

Caution must be taken to avoid life losses during the rescue work, the two leaders said.

Chinese vice-premier Zhang Dejiang arrived at the landslide site in Wulong county at 5 a.m. Saturday to oversee the rescue efforts.

At least 80 people are feared buried in the landslide at an iron ore mining area.

Rescuers had pulled out seven injured people, including four seriously hurt, from the debris as of 8:30 p.m. Friday, according to the publicity department of Wulong County.

The injured were taken to hospital.

The landslide happened at about 3 p.m. in the Jiwei Mountain area, in Tiekuang Township, about 170 kilometers southeast of the downtown area.

Millions of cubic meters of rock filled a valley and buried an iron ore plant and six houses.

The trapped included quarry workers, residents and possibly passers-by.

The landslide also cut off power and communications in many parts of the town.

More than 500 rescuers are searching for the missing.

Investigation into the cause of the landslide has begun.