The U.S. expects Beijing to respond to claims that Google and other firms have the subject of Internet attacks originating from China, Secretary of State Hillary Clinton said.

Google recently said it said it had discovered a "sophisticated and targeted attack on our corporate infrastructure originating from China".

It also said twenty other firms, which it did not name, had been targeted.

"We have been briefed by Google on these allegations, which raise very serious concerns and questions. We look to the Chinese government for an explanation," Clinton said.

"A primary goal of the attackers was accessing the Gmail accounts of Chinese human rights activists," Google said on its official blog.

"These attacks and the surveillance they have uncovered--combined with the attempts over the past year to further limit free speech on the web--have led us to conclude that we should review the feasibility of our business operations in China," the blog post also said.

WASHINGTON, January 13 (RIA Novosti)