Saudi Arabia claimed the barrier was necessary to protect from terrorism and smuggling weapons and illegal drugs—namely qat (and Yemen’s most important export, with border tribes reportedly earning upwards of £100 million a year). Specifically, Saudi Arabia claimed that smugglers provide weapons to radical Islamists within Saudi Arabia and were the source of explosives used in attacks like the 2003 Riyadh compound bombings, which killed 35 and injured over a hundred. Two years after the Yemeni Revolution of 2011, the country found itself a "haven for foreign terror fighters" where the Yemen-based Al-Qaeda in the Arabian Peninsula has "remained resilient and even enjoyed a resurgence".