None of the official U.S. government official's email account has been hacked, White House Press Secretary Jay Carney told reporters Thursday.

We have no reason to believe at this point that any official U.S. government email accounts were accessed, Carney said adding that FBI is investigating in to the matter.

Carney said all the U.S. government officials work is conducted on work email accounts and we have no evidence to suggest that any of those accounts were accessed or compromised.

Carney also said that though government officials are permitted to have personal email accounts, but are not allowed to use them in any official capacities.

Threats to information and communications infrastructure pose a serious economic and national security challenge for the United States and our partners, which is why the President has made cyber security one of his top priorities, Carney said.

Google claimed Wednesday that Chinese hackers were behind the recent hacking of several Gmail accounts, including senior U.S. government officials.

On the other hand, China has rejected Google's allegations and told reporters that efforts to put all of the blame on China were unacceptable.

Meanwhile, there have been serious allegations against the Chinese state machinery in the past over cyber attacks on the U.S. and allies. Experts have said in the past that, for China, cyber warfare fits into the scheme of things.

The hack attack came to light just a day after it was revealed that the U.S. government was planning to bring in legislation declaring cyber attacks as acts of war.

The US Department of Defense (DOD) announced on Tuesday that the military is ready to use force in response to cyber threats. The agency's cyberspace operations will fully commence next month but the country will not step back from using physical means to protect the country from any cyber attack that may prove to be a threat for the country.