SAN FRANCISCO – Microsoft says a security flaw in its Internet Explorer browser played a role in the recent computer attacks against Google and at least 20 other companies.

In a Thursday alert confirming the weakness, Microsoft said the security hole can be closed by setting browser's Internet security zone to "high." The world's largest software maker may also issue an update to fix the problem.

Microsoft pinpointed the trouble spot after Google announced earlier this week that hackers in China had pried into the e-mail accounts of human rights activists opposing the Chinese government's policies.

The attack outraged Google. It plans to leave China unless the government backs off rules requiring Google's Chinese search engine to censor some results.

MS refuses to use the same standards adopted by the other browser providers.