Pictures posted on blogs and Internet forums showed the bus consumed by flames. One badly burned and bloody woman was seen laying on the road with a man standing over her, his clothes burned off and his skin singed bright red.
A Web site run by the provincial government's propaganda department said 44 people were hospitalized, with 27 of those suffering severe injuries.
Neither report gave any indication of the cause of the fire, which broke out on a No. 9 city bus at about 8:30 a.m. (0030 GMT) as it passed near the city zoo.
Chengdu city government spokesmen reached by phone refused to offer additional information.
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