Extremist Islamic groups have come to value the internet so much for its ability to spread their message that some have said the keyboard is as important as a Kalashnikov rifle, a report for the US Congress says.

The report, to be presented to the Senate Homeland Security and Governmental Affairs Committee on Thursday, says terrorists have increased their use of the internet to make their activities faster, cheaper and more secure.

Use of the internet for communications, propaganda and research has grown to include recruitment and training, says the report prepared by a panel of experts brought together by George Washington University's Homeland Security Policy Institute and the University of Virginia's Critical Incident Analysis Group.