(Adds quotes, details on Beijing's response)
WASHINGTON, June 2 Google Inc's (GOOG.O) allegations that hackers, probably from China, sought to access the Gmail accounts of senior U.S. officials are very serious and the U.S. government is investigating them, U.S. Secretary of State Hillary Clinton said on Thursday.
"We are obviously very concerned about Google's announcement regarding a campaign that the company believes originated in China to collect the passwords of Google email account holders," Clinton told reporters.
"Google informed the State Department of this situation yesterday in advance of its public announcement. These allegations are very serious. We take them seriously, we're looking into them," Clinton said.
Clinton referred further questions on the matter to Google and to the FBI, which will conduct the U.S. investigation.
Google announced on Wednesday that suspected Chinese hackers tried to steal passwords of hundreds of Google email account holders, including senior U.S. government officials, Chinese activists and journalists.
The claim by the world's largest Web search company sparked an angry response from Beijing, which said blaming China was "unacceptable". This pointed to further tensions in Beijing's already strained relationship with Google and with Washington, which has been warily watching China's moves in cyberspace.
Clinton said the United States, which recently appointed its first ever cyber-security coordinator, believed cyber issues would be a continuing problem.
"We know this is going to be a continuing problem and therefore we want to be as prepared as possible to deal with these matters when they do come to our attention," Clinton said in an appearance in Washington with the Czech foreign minister. (Reporting by Andrew Quinn and Arshad Mohammed; Editing by David Lawder)