North Korean hackers have apparently sent spam e-mail messages to South Korean military officers, carrying viruses and malicious computer code, military officials here said Monday.

According to an official, senders who claim to be graduates of the Korea Military Academy in Seoul have written to about 60 current South Koran officers who graduated from the academy. Messages mostly included a benign greeting and attachment files, the official said.

"Our Cyber Command warned officers of these e-mails last Friday," the official said. "After tracing these messages, we believe North Koreans have tried to hack into (military information)."

The official said senders' addresses have used a South Korean domain, 'hanmail.net,' operated by a portal site Daum, including '1co3p@hanmail.net' and 'hoyon1241@hanmail.net.' He said hackers might not have been able to access any key military data since officers are restricted from accessing their Hanmail accounts on the base.

Opening the message or downloading an attachment file will activate malicious code, the official added.

"North Korean hacking attempts using the Hanmail domain appear to be spreading," the official said, adding that officers shouldn't open suspicious e-mails and should report to their respective cyber units immediately. (Yonhap News)