Rights groups have expressed concern over Thailand’s decision to send the Uighurs back to China fearing they could face ill-treatment and even torture.

Government spokesman Maj. Gen Verachon Sukhonthapatipak told The Associated Press that the group was put on a flight from a military airport outside Bangkok on Thursday morning.

A group of more than 170 Uighurs were identified as Turkish citizens and sent to Turkey, and almost 100 were identified as Chinese and sent back to China.

The attack was the latest in a series of nationalist-tinted protests in Turkey during the holy Muslim fasting month of Ramadan over China‘s treatment of the Turkic-speaking, largely Muslim Uighurs in the northwestern Xinjiang region. The group has complained of cultural and religious suppression as well as economic marginalization under Chinese rule.

Hua Chunying, a spokeswoman for China‘s foreign ministry, would not confirm whether the Uighurs had been deported to China but spoke in general terms about the issue at a daily news briefing on Thursday, saying the Uighurs were “firstly Chinese”.

“I strongly urge the Thai authorities to investigate this matter and appeal to Thailand to honor its fundamental worldwide obligations”, Volker Türk, UNHCR’s Assistant High Commissioner for Protection, said in a statement. “China said it would look after the safety of these people”, he said. The office was closed on Thursday.

Thai Prime Minister Prayuth Chan-ocha also held out the possibility of shutting the Thai embassy in Turkey after protesters attacked the honorary consulate in Istanbul, smashing windows and ransacking parts of the building, over the expulsion of the Uighurs back to China.

Police allowed the protesters to pray outside the consulate before taking nine of them away for questioning.

According to the Thai consulate, there are a total of 1,300 Thai nationals presently living in Turkey. They have traveled clandestinely through Southeast Asia to Turkey.

Ethnic violence in Xinjiang has left hundreds of people dead over the past two years.

The U.S. State Department and human rights groups like Human Rights Watch had urged Thailand to protect the Uygurs and not force them to return to China.

The World Uyghur Congress, a German-based advocacy group, said that those repatriated could face criminal charges and harsh punishment, possibly execution, under China‘s opaque legal system – the reasons they fled China in the first place.