More than a dozen ambulances were seen rushing to Riyadh’s international airport and travellers were evacuated from parts of the facility after a loud blast was heard there on Saturday, an eyewitness and people briefed on the matter said. Saturday’s incident comes amid an escalation of missile strikes by Yemen’s Iran-aligned Houthi on the kingdom. The airport has already been attacked twice this week, leaving four people dead and others wounded, and badly damaging an aircraft. The Saudi...