Twenty ethnic Uighur Muslims from China broke out of a detention center near the Thai-Malaysia border, Thai officials said Monday, after digging holes in the wall and using blankets as ladders.

The 20 were part of the last remaining group of more than 200 Uighurs who were detained in 2014.

Members of the group identified themselves as Turkish citizens and asked to be sent to Turkey but more than 100 were forcibly returned to China in July 2015, a move that sparked international condemnation, including from rights groups who feared they could face torture in China.