RIYADH - Saudi Arabia's security forces have found a pick-up truck packed with more than a tonne of explosives after raiding a militant cell primed to launch a "terrorist operation" in Riyadh, officials say. State television showed footage of the truck, seized after a clash on Tuesday in which two wanted militants were killed, filled with the explosives, rocket-propelled grenades and gas cylinders to magnify the force of any explosion. Officials say Tuesday's raid by security forces thwarted an imminent attack during the Muslim holiday of Eid al-Fitr, less than three weeks after suspected al Qaeda bombers killed at least...