Islamic State threatens to destroy Saudi prisons after executions

RIYADH (Reuters) - Islamic State threatened to destroy Saudi Arabian prisons holding jihadists after Riyadh's execution of 47 people including 43 convicted al Qaeda militants. The militant group, which has claimed responsibility for attacks in the kingdom and stepped up operations in neighbouring Yemen, singled out the al-Ha'ir and Tarfiya prisons where many al Qaeda and Islamic State supporters have been detained. ...