In a brief statement on its Twitter-like microblog, the zoo said investigators were looking into the cause of the incident, but offered no other details.
State media reports identified the victim as a 56-year-old man surnamed Zhou. They cited unidentified colleagues as saying the man entered the tiger enclosure to clean and "did not come out again."
The animal involved was identified as a highly endangered South China tiger, considered effectively extinct in the wild after decades of being hunted as a pest.
Built on a former golf course, Shanghai's zoo is one of China's largest and most popular urban animal parks.
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