Microsoft has issued a special patch for its Internet Explorer browser, to fix a vulnerability detected after the intrusion into Google in China.

The patch is being distributed through automatic updates, and everyone who uses IE should get it. Those who do not receive the fix automatically can download it.

The vulnerability allowed the insertion of a Trojan into a user's computer, which could then let in a remote user.

The Trojan is believed to have been delivered via emails sent to Google staff in China, and prompted a threat by Google to close its China operation, amid rumours that the intrusion was carried out by agents of the Chinese government, seeking to monitor the activities of political dissidents.

The incident has also prompted US Secretary of State Hillary Clinton to call for a global response to such attacks, and for unfettered access to the Internet worldwide.

"We need to create a world in which access to networks and information brings people closer together and expands our definition of community," Clinton said.

She also called on Chinese authorities to “thoroughly investigate” Google's allegations.

Clinton's speech may be the US government's sole formal response to the incident, rather than making a formal protest to China. Such a move would be difficult, given that the allegations remain unproven, and might also leave Washington open to charges of hypocrisy.

The US has been leading secret talks with a number of countries, including New Zealand, about a draconian intellectual property agreement called ACTA, and it was revealed this week that the FBI has been covertly seeking thousands of telephone records, allegedly to pursue terrorists.