Globalisation driving sweeping changes in world order

The study by the National Intelligence Council, called "Mapping the Global Future," also concludes the world is likely to witness impressive, but unevenly distributed, economic growth in the period through 2020. It rated the likelihood of great power conflict as lower than at any point in the last century.

But it said the key factors that spawned international terrorism show no sign of abating over the next 15 years, the study said.

"We expect that by 2020 al-Qaeda will be superceded by similarly inspired Islamic extremist groups, and there is a substantial risk that broad Islamic movements akin to al-Qaeda will merge with local separatist movements," the report said.

Information technology will allow terrorists to operate in an increasingly decentralized manner, and may enable them to arm themselves with biological weapons as know-how and technology moves online, the report suggests.

"Our greatest concern is that terrorist might acquire biological agents, or, less likely, a nuclear device, either of which could cause mass casualties," the report said.

Officials said more than a thousand US and foreign experts were consulted and some 30 conferences were held around the world to give the analysis a more global dimension.