WASHINGTON, US - SOME Defence Department computer networks have been infected with a 'global virus' and steps are being taken to mitigate it, the Pentagon said on Friday.

The acknowledgement followed reports that the military has banned the use of removable flash media like thumb drives or memory sticks in any Defense Department computer.

'We are aware of a global virus for which there are some public alerts on,' said Mr Bryan Whitman, Pentagon spokesman. 'And we've seen some of this on our networks. And we're taking steps to identify and mitigate the virus.'

Mr Whitman would not identify the virus or say what steps have been taken, and it was not known whether the virus had spread to classified computer networks.

The Military Times newspaper, however, cited a Nov 17 air force memo that ordered the 'immediate suspension' of the use of flash media on all unclassified and classified computer networks.

The Pentagon's global information grid includes about 17,000 local and regional networks and seven million individual computers, the newspaper said. -- AFP