Cyber-activists are mounting a co-ordinated attempt to disrupt the operations of eToys, a leading online toy store, and drive down the company's stock price.

So far the hacker attacks, which began on Wednesday, have been successfully rebuffed and eToys said yesterday it was confident the hackers' activities would have no averse effects on its business. However, the hacking incident appears to be one of the most blatant attempts to date at stock price manipulation using computer hacking techniques. It highlights the threat that co-ordinated hacking attacks may represent to the growing electronic commerce industry.

A group called RTMark is spearheading the attacks and calling upon other hackers to become involved. The self-proclaimed cyber-activists are protesting at eToy's trademark infringement lawsuit against a European artists' group called etoy. In November a US judge issued a preliminary injunction against the art group forcing it to stop using the name for its web site.

The attacks "take the form of an RTMark "mutual fund" or list of sabotage projects," the group said in a statement this week. "All projects in the 'eToy Fund', some of which have already been financed, aim to lower the company's stock market value as much as possible."

Since Wednesday, eToys' share price has dropped from Dollars 45 15/16 to trade in mid-session yesterday at Dollars 39, a 15 per cent decline. However, financial analysts said the drop was related to rising competition in online toy sales, rather than any concerns about hackers.

The hackers were using a sophisticated arsenal of tools to launch attacks on the web site yesterday, according to iDefense, a computer security monitoring service, which predicted that such protests would have a growing impact on e-commerce.

According to iDefense, RTMark gained notoriety during the recent World Trade Organisation meeting in Seattle, when the group created a mock WTO web site that mimicked the WTO's official site. The false site was used to urge protests against the WTO.

The group's activities demonstrate the potential for broad attacks on e-commerce companies that are perceived to have been involved in some sort of "injustice", iDefence said. "Contingency planning needs to incorporate the potential for a rapid onset of diverse attacks from any number of locations," the computer security group warned.

Yesterday there was little evidence to suggest that eToys' website was being affected by the hacker protest. However, access to the site was noticeably slower than in the past few days. The slowdown may have been caused by numerous factors including internet congestion or heavy use of the web site by shoppers.

EToys said its web site had the capacity to handle millions of shoppers and the company remained "one hundred per cent focused" on serving consumers.

* Two professors at the Massachusetts Institute of Technology have sued the online search service Ask Jeeves, claiming the site infringes two patents it holds in natural language question-and-answer technology, Reuters reports from Boston. Professors Patrick Winston and Boris Katz asked a court to stop Ask Jeeves from using the technology, and seeks damages and payment for royalties.