RIYADH, May 1 (Xinhuanet) -- Two Americans, two Britons and an Australian were killed in an attack on an engineering firm in the Saudi Red Sea port of Yanbu on Saturday, security sources said. According to the sources, all the five Western engineers worked for ABB Lummus, a subsidiary of Swiss-Swedish engineering and oil services giant ABB. The Saudi Interior Ministry earlier said in a statement that four men entered the headquarters of a Saudi contractor in Yanbu Saturday morning and fired at random at Saudis and foreigners. "There were a number of deaths and injuries among Saudis and foreigners,"...