Yemen-based al-Qaeda in the Arabian Peninsula (AQAP) attacked a Saudi border post along the Yemeni border on July 4, killing a Saudi border guard and a Yemeni soldier. Concurrently, Shiite Houthi rebels in Yemen seized control of the city of Amran. The events have once again prompted Saudi Arabia to put Yemen at the top of its national security concerns.
Some observers see similarities between developments in Yemen and what is happening to the north of Saudi Arabia with the escalating Sunni-Shiite sectarian conflict in Iraq and Syria and the advancement of the Islamic State (IS). IS has managed to gain strength and territory through an alliance with tribal forces that provide it with a popular base and means of support in both Iraq and Syria.