China on Monday dismissed accusations of any official involvement in hacking attacks on Google and other U.S. companies, adding to tension between the two countries over the issue.

A Chinese official also defended online censorship of political topics and said the country would not change how it regulates the Internet, according to the official Xinhua news agency.

Google has said it was hit by cyberattacks from China that caused the loss of intellectual property and were also aimed at accessing the Gmail accounts of Chinese human rights activists. Google cited the attacks, which hit at least 20 other large U.S. companies, as one reason it plans to stop censoring its Chinese search engine, even if that means closing its China offices.

Google did not blame the Chinese government for the attacks, but U.S. Secretary of State Hillary Clinton has called on China to investigate the claims.

"Whether through explicit or implicit means, criticizing 'Chinese government participation in hacking attacks' is totally baseless," China's official Xinhua news agency cited a spokesperson for China's IT ministry as saying. "We resolutely oppose this." The Xinhua article quoting the ministry official was posted on the ministry's Web site.

The official repeated previous government statements that Chinese law forbids hacking attacks and that the country is open to international cooperation to fight cybercrime.

A spokesperson for China's State Council said the country's laws protect freedom of speech online but also forbid use of the Internet for acts such as subverting the government, destroying national unity or spreading porn or violent content, according to a separate Xinhua report.

"China's handling of this harmful information according to the law has a full legal basis, and without a doubt is a totally separate issue from so-called 'restrictions on Internet freedom,' " the official was quoted as saying. "We will steadfastly walk the path of Internet development and oversight with Chinese characteristics."

China's foreign ministry last week said Clinton had harmed U.S.-China relations by urging Internet freedom in countries including China.

China requires the local search engines of Google and other companies to remove certain sensitive items from search results, including porn and political content such as information about the 1989 democracy protests in Beijing's Tiananmen Square. Local authorities also patrol the Web for such content and sometimes punish Internet companies that allow it to appear on their sites, including on user-generated pages such as blogs.

Google is still censoring search results on its Chinese search engine, but company CEO Eric Schmidt last week said that could change soon.