The attack in India's financial capital is a "turning point" in tactics adopted by terrorists in such operations, officials including those from the FBI and New York Police Department concluded while testifying before a Congressional Committee on lessons learnt from the Mumbai attack.

It becomes all the more necessary to bring perpetrators to justice, otherwise there could be more and more such attacks, they said.

With the basic weapons they had, 10 terrorists created a mayhem that killed or injured almost 500 people. So, it could very well be a "turning point" in the sense of relative simplicity of the attackers, said Raymond W Kelly, the New York City Police Commissioner in response to a question from Senator Joseph Lieberman, Chairman of the Senate Committee on Homeland Security and Governmental Affairs.

"This attack was clearly successful and groups would look to emulate this model in other parts of the world as well," said Donald N van Duyn, FBI's chief intelligence officer.

"The principal lesson from the Mumbai attacks reinforces the notion that a small number of trained and determined attackers with relatively unsophisticated weapons can do a great deal of damage. We sometimes focus on tactics that may be exotic and esoteric ... but for most terrorists, they're looking for what works," he said.

Referring to the use of media, especially the electronic media, Duyn said: "Terrorists are very attuned to the media and they saw the success... Some groups may look to this as a model".

Duyn said while governments across the world were concentrating on biological and chemical weapons and radiological attacks, the Mumbai attacks have shown that terrorists can achieve a lot of their objectives through low-tech equipments without using any of those tactics.