Email communication in the Marshall Islands was paralysed after hackers launched a "zombie" computer attack on the western Pacific nation's only Internet service provider, officials said.

Email communication in the Marshall Islands was paralysed Tuesday after hackers launched a "zombie" computer attack on the western Pacific nation's only Internet service provider, officials said.

The attack starting early Tuesday, in which hackers used computers taken over by viruses to flood the Internet provider with spam emails, caused a complete shutdown of email traffic into the nation of around 55,000 people.

More than 18 hours after the initial attack Tuesday incoming email service to the monopoly provider had still not been restored.

The government-owned National Telecommunications Authority (NTA) was hit with a sudden four-fold increase in incoming email, which it described as an attack by "zombie computers", said an NTA spokesman.

While NTA customers could send and receive emails to each other through the local system, virtually no non-NTA emails had been received since Monday, impacting local businesses, banks and government offices.

"Some malevolent person unleashed infected computers to flood NTA with mail," said a local information technology expert who asked not to be named.

"The fact that there were so many messages sent shows a degree of sophistication to the attack."

Local officials said the cyber attack was believed to be the first on the country's only Internet service provider.

© 2008 AFP