The US government has admitted the nation's power grid is vulnerable to cyber attack, following reports it has been infiltrated by foreign spies. WASHINGTON -- Cyberspies have penetrated the U.S. electrical grid and left behind software programs that could be used to disrupt the system, according to current and former national-security officials. The spies came from China, Russia and other countries, these officials said, and were believed to be on a mission to navigate the U.S. electrical system and its controls. The intruders haven't sought to damage the power grid or other key infrastructure, but officials warned they could try during a crisis or war. "The Chinese have attempted to map our infrastructure, such as the electrical grid," said a senior intelligence official. "So have the Russians." The espionage appeared pervasive across the U.S. and doesn't target a particular company or region, said a former ...