BEIJING (AP) -- Microsoft has agreed to show China's government the underlying source code for its Windows software in an attempt to reassure the regime about the integrity of its computer operating systems.

The announcement was made Friday during a visit to Beijing by company chairman Bill Gates, who said Microsoft was intent on providing the "maximum level of cooperation" in assuring governments of network security.

"This is such an important agreement for us, and such a milestone in our relationship with China that we chose to do it at a time when I was here in China," Gates said at a news conference.

Along with other governments, China worries that over-reliance on Windows software could make it vulnerable to high maintenance costs and safety loopholes. China's occasional rivalry with the United States also arouses nationalist objections to relying on Redmond, Wash.-based Microsoft, partly out of fear electronic "back doors" could be built in giving the company or the U.S. government access to Chinese secrets.

Some officials and technical advisers have suggested using open-source software such as Linux, which can be used and modified for free, unlike Microsoft's proprietary code, which is kept secret.

China follows NATO, Russia and Britain in signing the "Government Security Program" with Microsoft. Gates said the agreement gives governments controlled access to the entire Windows source code, including all improvements and new versions of Windows.

He said access to the code will let governments evaluate for themselves the security of the Windows platform. It also will give them the technical data they need to develop their own secure applications to work on top of Windows.

"It's part of the commitment to make sure that governments and industries are working together in the best possible way," Gates said.

Gates said the agreement with China had been under discussion for several months. Microsoft is in talks with 30 other governments to sign the agreement, the company said.

Gates met earlier in the day with Chinese President Jiang Zemin and said both men were "very optimistic about the view ahead" for technology.

"I wanted to get his view on how China is developing and the best way for Microsoft to be a very strong partner here in China," Gates said.

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