Emergency vehicles rushed to the navy yard after the attack which happened early Monday as employees were starting work in a building housing the Naval Sea Systems Command headquarters. _____________________We have known no motive at this stage. President Obama, speaking not far away at the White House, called it a cowardly act. Luis Ramirez, VOA news, at the Pentagon. 当海军海上系统指挥总部办公楼的员工在周一早上正准备投入工作之时,袭击发生了,之后,急救车辆赶到了海军大院.______________________到目前为止,我们还不清楚袭击的动机. 奥巴马总统在附近的白宫发表讲话,声称这是一种懦弱的行为.VOA新闻,刘易斯.拉米雷斯在五角大楼为您报道.