More than 1,200 Yemeni prisoners including suspected al-Qaeda members escaped during a breakout Tuesday, Reuters reported.

The escape from the facility in Taiz, Yemen, came as Shiite Houthi fighters were advancing on the city. According to reports, sympathizers of al-Qaeda, comprising Sunni fighters, attacked the jail and freed the prisoners before the Houthis could arrive.

The violence and lack of stability in Yemen led to the U.S. suspending Guantanamo Bay prisoner transfers there even though the bulk of the remaining detainees are Yemeni.

For several months, Saudi Arabia and a coalition of Arab nations has conducted regular airstrikes on Yemen to push back the Houthi rebels. Most of the country, however, remains under Houthi control and has suffered an escalating humanitarian crisis.