Security experts are warning PC users to be on guard against viruses masquerading as Valentine’s Day messages, which could damage computers.

“Computer users should keep a wary eye on any romantic messages received by e-mail, as many of them could contain malicious code,” said US security firm PandaLabs after detecting an increase in a worm it dubbed Nurech.A.

The worm hides in emails with subjects like: “Together You and I,” “Til the End of Time Heart of Mine.”

People who open an attached file such as postcard.exe can end up infecting their computers.

Security firm Symantec said it had detected “large-scale spamming” of e-mails including a Trojan horse, a program that contains or installs a malicious program.

Symantec said the malware was a new version of Trojan, Peacomm or the “Storm Trojan.”

“With Valentine’s Day approaching, this time around the authors are attempting to tug on the heartstrings of unsuspecting users with romantic subject lines such as ‘My Heart belongs to you,’ said Symantec’s Orla Cox.