Foreign ministry spokesman Qin Gang said government officials summoned Google representatives and told them to "remove the material immediately."
"We have found that the English version of google.com has spread lots of pornographic, lewd and vulgar content, which is in serious violation of Chinese laws and regulations," he said.
Meanwhile, U.S. officials have sent a letter to China’s leaders, calling on them to revoke its order for the Green Dam Youth Escort filtering software to be pre-installed or supplied on a disc with all new PCs in China starting July 1.
U.S. Commerce Secretary Gary Locke and Trade Representative Ron Kirk in the letter said the new initiative "poses a serious barrier to trade" and said the software might pose security risks.
"China is putting companies in an untenable position by requiring them, with virtually no public notice, to pre-install software that appears to have broad-based censorship implications and network security issues," Locke said.
Locke and Kirk's letter said China might have violated World Trade Organization regulations that require governments to give companies advance notice of rule changes, as well as a time to comment.
"Protecting children from inappropriate content is a legitimate objective, but this is an inappropriate means and is likely to have a broader scope," Kirk said.
"Mandating technically flawed Green Dam software and denying manufacturers and consumers freedom to select filtering software is an unnecessary and unjustified means to achieve that objective, and poses a serious barrier to trade," he said.
In related news, China's Ministry of Health will start blocking sex-health websites, as well. The ministry said the sites being used as an excuse for publishing porn.
"The ministry will strengthen its management and supervision of sex health websites in the country to guarantee scientific and accurate information and prevent lewd content in disguise," spokesman Deng Haihua said.
The measures, which will take effect after July 1, specify that healthcare websites cannot pick up content from illegal publications and must take full responsibility for their content, including information linked to from their sites.
Fines of up to $4,400 can be levied for distributing obscene content under the guise of conducting sex research.