BEIJING, Dec. 26 (Xinhua) -- Chinese authorities on Wednesday blamed loose supervision over engineering and construction for a deadly landslide that killed 35 and cut off a road for 24 days in central China.

    A statement jointly released by the Ministry of Railways and State Administration of Work Safety said investigations showed the explosion procedures separated rock on the edge of the tunnel, through which a long-distance bus was passing. It separated the rock from its parent rocks and caused an avalanche of about 3,000 cubic meters of rubble.

    This was the direct cause of the landslide that engulfed the ill-fated bus on the highway in Badong County, Enshi Prefecture of Hubei Province on Nov. 20, the statement said.

    "Although the causes of the accident were complicated, the accident revealed management negligence and loose control over engineering and construction on the part of units engaged in construction, geo-technical engineering and monitoring," it said.

    The construction site where the accident took place belonged to a company under the China Railway Tunnel Group. It was designed by China Railway Siyuan Survey and Design Group Co. Ltd.

    Sichuan Tieke Construction Project Management Company was responsible for construction monitoring. Yiwan Railway Project Construction Headquarter under the Wuhan Railway Bureau built the site.

    The statement said all-level railway and work safety authorities should step up examinations on railway construction projects and search for hidden troubles during construction.

    The slide killed 32 passengers on a bus and three road maintenance workers. Another worker at the site suffered slight injury.

    The slide site was about four hours drive from the Three Gorges Dam, the world's largest hydropower project.

    A 100 meter section of the No. 318 highway, which linked Shanghai to Tibet, was closed after the slide. During the blockage, up to 5,000 vehicles were forced to make a 30-minute detour 17 kilometers away, according to local traffic authorities.

    More than 100 workers exploded loose rocks and reinforced roadside mountains during a three-week period. Traffic resumed on Dec. 13.