US President Barack Obama is "troubled" by cyberattacks on Internet titan Google and wants answers from China, the White House said.
The State Department said meanwhile that US and Chinese diplomats have held several meetings to discuss the attacks, which Google said targeted the email accounts of Chinese human rights activists, and more talks were expected.
"We are having high-level meetings and we will continue to have meetings and we will continue to press this issue aggressively," State Department spokesman Philip Crowley said. "We will continue to seek an explanation from China.
"A blanket denial that nothing happened we don't think is particularly helpful," Crowley added.
Obama is also looking to Beijing to shed light on the cyberattacks which have prompted Google to say it will stop censoring Web search results in China, a move that may force it to leave the country entirely.