ISIS have threatened to destroy Saudi Arabian prisons holding jihadists following the execution of 47 people by Saudi authorities on Saturday. The terrorist organisation have singled out the al-Ha’ir and Tarfiya prisons where many al Qaeda and ISIS supporters are being detained. Reuters.com reports: “The Islamic State always seeks to free prisoners, but we calculate that the ending of the issues of prisoners will not happen except with the eradication of the rule of tyrants, and then destroying their prisons and razing them to the ground,” it said in an article posted online on Tuesday. An Islamic State supporter killed himself in a car bomb at a checkpoint outside Ha’ir prison near Riyadh in July. While Islamic State and al Qaeda are rivals who have condemned each other on ideological grounds, they are both united in enmity towards Saudi Arabia, which has declared them terrorist groups and locked up thousands of their supporters. Riyadh’s mass execution on Saturday included four Shi’ite Muslims, among them prominent cleric Nimr al-Nimr, a move that heightened sectarian tensions with Shi’ite power Iran. But anamysts say it was mostly meant as a message to militant Sunnis. Islamic State has claimed responsibility for a series of bombings [...]