WASHINGTON, June 22 (Reuters) - The United States wants China to revoke its order that software filters be installed on personal computers starting next month, a U.S. official said on Monday.

Critics say China will use the filter, known as "Green Dam," to tighten censorship of the Internet, but China says it is designed to block pornography. It is requiring that the filters be pre-installed on all new computers made or shipped after July 1.

"We would like to see the Green Dam mandate revoked, and will continue efforts to convince Chinese authorities to do so," a U.S. official said, speaking on condition of anonymity.

The introduction of Green Dam has raised concerns from industry as well as rights groups who cite worries including compatibility, intellectual property rights and support for the software to cybersecurity and Internet freedoms.

The filter program is sold by Jinhui Computer System Engineering Co.

"We hope that China will look at the broad array of concerns that the Green Dam mandate has prompted from its own citizens, from global PC companies, and from other governments, and revoke this measure," the Obama administration official said.

Washington has been raising its concerns about the filter with relevant Chinese agencies that have responsibility for trade and political ties with the United States, the official said.

Officials from the State Department, the U.S. Trade Representative's office and the Commerce Department who are based at the U.S. embassy in Beijing have discussed the filter with government officials from Chinese ministries dealing with commerce and information technology, the U.S. official said.

In China, the U.S. embassy has said it views with concern any attempt to restrict the free flow of information.

Some Internet users in China are urging people to stay offline on July 1 to protest the rule.

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