Thai lawmakers, activists, and lawyers believe a group of Uyghur men detained in Thailand for more than a decade may have been deported to China early Thursday after trucks with covered windows were seen leaving a detention center and China said Chinese citizens had been repatriated from the Southeast Asian country.

Authorities in Thailand on Thursday deported dozens of Uyghur men to China, despite vehement public objections and weeks of behind-the-scenes diplomacy from the U.S. The men had been in Thai detention for more than a decade after fleeing China’s Xinjiang region,