Attacks on information systems are ``as serious a threat as this country faces,'' said Senator Chuck Robb of Virginia, who endorsed a report released by the Center For Strategic and International Studies, (CSIS) a Washington think tank.

The report warns dramatically that US defence capabilities and its economy are practically at the mercy of computer mercenaries, `cybercriminals' and `cyberterrorists.'

US law enforcement agencies are ``five to ten years behind the transnational crime curve,'' a gap at least partially attributable to the fact that it takes a government agency an average of 49 months to buy, install and use a new computer system, versus nine months in the private sector.

The report `Cybercrime, Cyberterrorism, Cyberwarfare' says that information warfare specialists at the Pentagon estimate that a properlyprepared and well coordinated attack by fewer than 30 computer virtuosos around the world, with a budget of less than 10 million dollars, could bring the United States to its knees.

Such an attack ``would shut down everything from electric power grids to air traffic control centres,'' the report says.

``America's adversaries know that the country's real assets are in electronic storage, not in Fort Knox. Virtual corporations, cashless electronic transactions, and economies without inventories... will make attacks on data just as destructive as attacks on actual physical inventories.

``Bytes, not bullets, are the real ammo,'' the report said.

Using the tools of information warfare, cyberterrorists can overload telephone lines with special software; disrupt the operations of air traffic control as well as shipping; scramble software used by major financial institutions; alter the formul as for medication at pharmaceutical plants; change the pressure in gas pipeline to cause a valve failure; and sabotagethe New York Stock Exchange.

The CSIS offered some recommendations, most notably that the President order an exhaustive review of the dangers inherent in computer technology and that the military and computer establishments do more to prepare themselves to confront the new challenges.