CORRECTED - Militant groups multiply as conflict changes-IISS

(Corrects name in second para to International Institute for Strategic Studies)

By Luke Baker

LONDON, Feb 5 (Reuters) - Nearly 400 militant groups now operate around the world and the greatest proliferation has been in the border regions between Afghanistan, Pakistan and India, an annual military report showed on Tuesday.

The number of violent "non-state" groups has grown about 10 percent in the past year, according to the 2008 Military Balance report by the International Institute for Strategic Studies.

Iraq and India, with more than 30 active guerrilla groups each, are the most volatile countries. The Afghan/Pakistan border and the Kashmir region between India and Pakistan are the worst affected areas, with a total of 65 groups in operation.

"It reflects the changing nature of conflicts over the past 10 to 15 years," said Nigel Inkster, the director of transnational threats and political risk at IISS.

"We're seeing less and less inter-state conflict and more and more intra-state conflict involving a wide variety of armed groups -- the number just keeps on spiralling."

Inkster, a former director of operations with Britain's Secret Intelligence Service, said the fastest growing threat came not from al Qaeda or any of its offshoots in Iraq, but probably Tehrik-a-Taliban, a Pakistani Taliban movement.

Led by Baitullah Mehsud, an ethnic Pashtun tribal warlord, the group has a base in Waziristan, in the Pakistan/Afghanistan border region, and has recently expanded to align itself with global struggles.