Muslim states said they were "deeply concerned" on Tuesday by riots which left at least 156 people dead in China's Xinjiang region, where Muslim Uighurs form the largest ethnic group.
The Organisation of the Islamic Conference deplored the "disproportionate use of force," calling upon Beijing to open an "honest probe over the seriously dangerous events and to bring those responsible to justice".
"It seems from the huge number of civilian casualties that there has not been cautious and proportionate use of force and firepower," the Jeddah-based grouping of 57 Muslim countries said in a statement.
It called on Beijing to address the "problem of Muslim groups and communities in China in a broad manner that would address the roots of the issue."
At least 156 people were killed and more than 1,000 wounded when violence erupted in the capital of China's northwestern Xinjiang region, Urumqi, on Sunday after decades of simmering tensions between Uighurs and Han Chinese.
Several human rights groups have expressed concern over the fate of 1,434 people who were taken into police custody, saying they could be tortured or mistreated.