Saudi Arabia declared a UAE-backed separatist advance in Yemen as a threat to Riyadh's national security, after a Saudi-led coalition said it struck a UAE weapons shipment destined to Yemen's STC separatist forces. The latter, backed by Abu Dhabi, are seeking to revive the formerly independent state of South Yemen thirty years after the country's unification. They made sweeping territorial gains after launching a lightning offensive in recent weeks. Jon Gambrell, Associate Press reporter, tells us more.