Computer users are being warned about new malware that purports to be pictures of a captured Osama Bin Laden.

The emails arrive with a variety of headers such as 'God Bless America' or 'Captured at last' and contain an attachment with the malicious code.

The message reads: "Turn on your TV. Osama Bin Laden has been captured. While CNN has no pictures at this point of time, the military channel (PPV) released some pictures. I managed to capture a couple of these pictures off my TV. I've attached a slideshow containing all the pictures I managed to capture."

Once opened, the Trojan, named Psyme, copies itself onto the PC and sends a message to a website confirming the infection.

Millions of copies of the emails have been spammed out since 2 June, according to email management firm Blackspider Technology.

"We have run global checks and over a million copies have been sent so far," said Emma Dunstone, marketing manager at Blackspider.

"It seemed to kick off around the end of the American working day and has been spreading ever since. Antivirus firms do have a patch available, but it took them over three hours to build one. That's quite a window of opportunity."

The emails use elementary social engineering techniques first popularised by the 'I Love You' virus, which masqueraded as a letter from a secret admirer.