Secretary of State Hillary Clinton said that the US government is studying Google's "very serious" allegations of a cyber spying campaign originating in China.
"These allegations are very serious. We take them seriously. We are looking into them," Clinton told reporters after saying Washington was "very concerned" by Google's announcement.
China said it was "unacceptable" to blame it for a cyberspying campaign which Google said had targeted the Gmail accounts of senior US officials, journalists and Chinese activists.
The comments marked the latest salvo in a battle between the Chinese government and Google dating back to last year when the US Internet giant revealed it had been the victim of a separate China-based cyberattack.
Google said Wednesday it was hit by a cyberspying campaign that appeared to have originated in Jinan, capital of the eastern Chinese province of Shandong.
The company did not specifically point the finger of blame at Chinese authorities.
Clinton said the company had informed the State Department on Wednesday about its claims before disclosing them publicly.
White House spokesman Jay Carney told reporters meanwhile that President Barack Obama is "obviously aware" of the Google allegations and "updated on these sorts of things regularly.
"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 cybersecurity one of his top priorities," Carney said.
"As with all intrusions, we employ an all-of-government approach with the appropriate agency in the lead. In this case, the FBI is coordinating a response," he added.
"We're looking into these reports. We have no reason to believe, at this point, that any official US government email accounts were accessed," he said, referring reporters to the FBI for further details.