Thai authorities confirmed on Thursday that they have repatriated 90 Uyghur asylum seekers, detained by immigration authorities for over a year, to China.
Deputy government spokesman Major General Werachon Sukondhapatipak confirmed the deportation in a statement to radio station FM 100.5, Efe news agency reported.
Werachon said the process was carried out "under the agreement that their safety is guaranteed according to humanitarian principles".
The UN High Commission for Refugees (UNHCR) criticised the deportation of the Uyghurs to China by Thai authorities, as many of them were sent against their will.
In a statement, UNHCR urged Thailand to meet its obligations and allow around 50 Uyghurs, still on Thai soil, to be sent to a third country.
"We are shocked by this deportation of around 100 people and consider it a flagrant violation of international law," said Volker Turk, UNHCR's assistant high commissioner for protection
Meanwhile, the Thai consulate in Istanbul remained closed Thursday, following an attack that caused material damage, by the Uyghur minority group in Turkey on Wednesday night.
Thailand's foreign ministry reported no injuries and urged its 1,300 citizens in Turkey to "be on alert".
Thai authorities had arrested a group of 408 illegal immigrants, including several Uyghur Muslims, in southern Thailand in early 2014.
It recently sent 173 Uyghurs to Turkey, following a bilateral agreement, the 'Bangkok Post' reported on Wednesday.
Thai authorities believe the Uyghurs -- an ethnic minority from the northwestern Chinese region of Xinjiang, said to be from Turkey originally -- were fleeing persecution by the Communist government in China.
Xinjiang is one of the hotspots in China after decades of conflict between local Muslim Uyghurs and the Chinese Han majority.