Apple says it "recently discovered that a small number" of Video iPods shipped with a virus that can affect computers running Microsoft's Windows.

The company says less than one per cent of the Video iPods sold since Sept. 12 this year were infected with the RavMonE.exe virus before they left a manufacturing plant.

The virus only affects Windows computers, but it spreads itself to other computers via mass storage devices such as removable hard disks and USB flash memory drives. 

That means that if someone infects a Windows machine with the virus from a Video iPod and then uses a removable storage device on that PC, they could spread the virus to other machines that the storage gadget is later connected to.

The company is playing down the problem, saying it has had "less than 25 reports" of customers detecting the virus after connecting a Video iPod to a computer, but it's still an embarrassment for the Mac maker.

Apple tried to place some of the blame for the incident on Microsoft, saying on a support website that, "As you might imagine, we are upset at Windows for not being more hardy against such viruses, and even more upset with ourselves for not catching it."

Security company McAfee rates the virus as low risk, and it can be detected and removed from Windows machines using current anti-virus software.

People with infected iPods have to use iTunes 7 to restore the software on the players.

Due to the risk of spreading the virus via removable drives, Apple's support site says, "We recommend that you scan any mass storage devices that you have recently attached to your Windows computers such as external hard drives, digital cameras with removable media, and USB flash drives."

Apple says no other iPod models are affected. It has not issued a recall for the Video iPod.