It's the second time Google has blamed a major computer hacking scheme on China, reports CBS News correspondent Wyatt Andrews.
This time Google says unknown hackers from Jinan, China, a city with a military command center, stole the personal Gmail passwords of hundreds of senior U.S .government officials.
Google said the hackers' "goal" was to eavesdrop on the officials -- "to monitor the content of the users' emails."
That suggestion -- of spying -- rang alarm bells in the Administration.
"These allegations are very serious," said Secretary of State Hillary Clinton. "We take them seriously. We're looking into them."
According to a respected security blogger -- the attack that targeted the State Dept. looked like an innocent looking email offering the latest U.S./China joint statement -- but if the reader clicked on the document, what appeared next was a Gmail log in page -- which was fake -- and which fooled some users into giving up their private passwords.
The hackers did not steal any government-owned emails -- but U.S. officials who work at home frequently use Gmail to do government business. White House teams often use Gmail to communicate where and when the President might travel. The risk is growing that too much secure information is being sent on non-secure systems.
"Anyone who works in government should not be using a personal email account such as one that would be found in Gmail on Google to put any classified information or government activity information," said retired General Harry Raduege.
China denies the hacking is state-sponsored, calling that allegation, "completely unfounded and made with ulterior motives."
But the FBI is now investigating -- and this new revelation of hacking is adding heat to the growing friction between the U.S. and China.