Washington scrambled on Thursday to assess whether security had been compromised after Google Inc revealed a major hacker attack targeting U.S. officials that the Internet giant pegged to China.

These allegations are very serious, Secretary of State Hillary Clinton said.

We take them seriously; we're looking into them, Clinton told reporters a day after the Internet giant said it had disrupted a campaign aimed at stealing passwords of hundreds of Google email account holders, including senior U.S. government officials, Chinese activists and journalists.

Google's announcement fuels debate in Washington over China's intentions in cyberspace, which the United States has identified as a potential flashpoint for future conflict.

Neither Google nor the U.S. government has said the Chinese government was behind the attacks. Google only said the attack appeared to originate in China.

Beijing nevertheless reacted angrily to Google's charge, saying it was unacceptable to blame Beijing and allegations that China supports hacking were unfounded and have ulterior motives.

Clinton said Google told the State Department before it made its public announcement on Wednesday, and that the U.S. Federal Bureau of Investigation was investigating, with Google.

U.S. officials, speaking on background, said they had no indication of any security breach, noting government employees were directed not to use private accounts to discuss sensitive issues. Some agencies, including the Securities and Exchange Commission, block employees from accessing personal accounts.

Also, the White House said it had no reason to believe official government emails were hacked in the Google incident.

Still, the government will check whether senior officials' private accounts were targeted, said one official, speaking on condition of anonymity.

There is a lot of awareness that whether it's a hostile intelligence service or others who may want to access this, the official said.

DUELING IN CYBERSPACE

Google's latest salvo looked likely to bring Internet policy to the foreground in the U.S-China relationship, where Washington and Beijing have staked out sharply contrasting approaches to censorship, freedom of speech and cybersecurity.

The United States was drawn in last year when Google temporarily shut its Chinese-language portal over censorship concerns and a cyber attack it said was traced to China. Clinton also has accused Beijing of facing a dictator's dilemma as it seeks to control technologies that are fueling growth and free speech around the world.

The dispute over the Internet has at times amplified existing strains in the U.S.-China relationship on everything from human rights and trade to intellectual property rights.

Clinton said the United States, which recently unveiled its first ever national strategy on cyberspace, believed cyber issues would continue to be a 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 with the Czech foreign minister.

Both the White House and the State Department have appointed officials to oversee cybersecurity issues, while the Pentagon probably has the most developed strategy in the U.S. government, with a Cyber Command and thousands of people in different divisions of the military dedicated to matters of cybersecurity and cyberwafare.

The United States has warned that a devastating cyberattack could result in real-world military retaliation, although analysts say it could be difficult to detect its origin with full accuracy.

The State Department's cyber coordinator, Christopher Painter, called cyber security a diplomatic priority for the United States as it seeks to defend itself from threats ranging from freelance hackers to militants to potential rival states.

The most important thing is to build international consensus....It's not just China that we need to engage with. It is an important part of our agenda with every country, Painter told Reuters on the sidelines of a London conference.

Blackberry maker Research In Motion and Microsoft Corp. could get a boost from the Google hacking incident. The companies have been fending off competitive challenges from Google's Android software and cloud computing services, as the corporate sector and the federal government explore whether Google is a secure alternative for e-mail and other communications.

(Additional reporting by Arshad Mohammed and Phil Stewart in Washington and Peter Apps in London; Editing by Cynthia Osterman)

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