Sunbelt Software, a provider of security software in Clearwater, Fla., had alerted users on its blog on Thursday that the bank's site had been compromised, and advised them not to visit the site.

Unidentified hackers had inserted malicious code into the bank's main webpage, a senior employee familiar with the situation said on Tuesday, speaking on condition of anonymity. The bank's designated spokesman on this issue was not immediately available for comment.

As a result, people coming to the bank's website were likely to be temporarily redirected to another site where Trojans and other malware were downloaded onto their computers, the employee said. The user was then brought back to the bank website.

The bank's IT staff thought they had the situation under control Friday morning, until they found that each time they changed the index page for the website, it was immediately replaced by the hackers. The bank then decided to bring the website down.

"The website was hosted externally by a hosting company in the U.S.," the employee said. The bank has since changed the company hosting the service, though the employee clarified that the change in hosting provider had been in the cards even before the hacker attack.

The attack on the website did not, however, affect the bank's online banking operations, according to the employee. The bank's customers access online banking services through a link on the homepage of the bank's website. The online banking service is provided to users from well-protected servers hosted and monitored within the bank by Hewlett-Packard, the employee said.

The bank is as yet not clear about the identity of the hackers, although Sunbelt suggested in its blog that it was a criminal gang, called the Russian Business Network. "We have called for the logs from the hosting provider in the U.S., and we may have some definite information then," the employee said.