China's embassy in Turkey has issued a travel warning to its citizens after some tourists were "attacked and harassed" during anti-Chinese protests in Istanbul.The Chinese and Turkish governments are at odds over China's treatment of the Uyghurs, a predominantly Muslim ethnic group that live in China's far western Xinjiang province.In a statement on its website, the Chinese embassy told Chinese tourists to be aware of their safety and avoid going out alone. It also advised them not to get close to protesters or photograph them.At the weekend, there were a series of anti-Chinese protests in Istanbul in support of Uyghurs, during which some demonstrators were seen burning Chinese flags.In one incident, Turkish television showed police intervening on Saturday to stop demonstrators.