SHANGHAI—The state-approved leader of China's largest mosque by size was killed in the far western Chinese city of Kashgar, according to multiple accounts, in the latest violence in a region beset by ethnic and religious strife.

Jume Tahir was killed Wednesday shortly after attending morning prayers, according to the state-run Xinhua News Agency and ts.cn, an official news source run by the government in Xinjiang. Mr. Tahir was the leader of Kashgar's ancient and symbolic Id Kah Mosque.

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