"The Mumbai attacks illustrate, the simplest of weapons can be quite deadly when combined with capability and intent," Robert Mueller said in his speech at the prestigious Council on Foreign Relations.

Delivering a lecture on "Global Terrorism: The FBI's Role," Muller devoted a considerable part of his speech to the Mumbai attack and the lessons FBI has learnt from it as he believes such a thing could be replicated in the US and other parts of the world as well.

"It again raises the question of whether a similar attack could happen in Seattle or San Diego, Miami or Manhattan," he said.

Observing that the Mumbai attack was both highly coordinated and deceptively simple in execution, Muller said: "This type of attack reminds us that terrorists with large agendas and little money can use rudimentary weapons to maximize their impact."

Nearly 180 people, including several American nationals, were killed in the attack launched on November 26.

The FBI has played a crucial role in helping India investigate the attack and find out who all were involved and where did the attackers came from.

"Even before crisis ended, the investigation began," Muller said.

"One pattern in particular concerns us. Over the years since September 11th, we have learned of young men from communities in the United States, radicalised and recruited here to travel to countries such as Afghanistan, Iraq, Yemen or Somalia. They may be recruited to participate in the fighting, or in the extreme case to become a suicide bomber," Muller said.

"A man from Minneapolis became what we believe to be the first US citizen to carry out a terrorist suicide bombing. The attack occurred last October in northern Somalia, but it appears that this individual was radicalised here in the United States, in his hometown in Minnesota," he said.

"The prospect of young men, indoctrinated and radicalised within their own communities, and induced to travel to such countries to take up arms, and to kill themselves and perhaps many others, is a perversion of the immigrant story," he said.

Muller said a number of individuals have travelled to Pakistan or Yemen or Somalia from the US. "They may be Somali or they may be converts who are not necessarily out of the Somali community but have gone over to Somalia to train and to fight," he said.