Saudi Arabia beat Britain to become the world's fourth largest defence spender in 2013, a report said on Wednesday, as Western cuts and Asian and Middle Eastern growth shift the global balance of military power. London's International Institute for Strategic Studies said the United States remains by far the world's pre-eminent military power, spending some $600 billion Last year, some 38 percent of the global total.

Overall global defence spending probably fell marginally in 2013, it said, but increased dramatically in Asia and the Middle East. China's military expenditure had increased by some 40 percent since 2010, raising it to an estimated $112 billion. That in itself is helping spark a wider Asian arms race, the report said, with Japan, South Korea, Vietnam and others also ramping up spending. Despite a US "pivot" to reallocate military forces to Asia, analysts say some countries - particularly Japan, locked in growing confrontation with Beijing over disputed maritime boundaries - worry that Washington might fail to back them in any conflict. Overall, Asian military spending in 2013 was 11.6 percent higher than in 2010, it said.

In the Middle East, Gulf Arab state worries over Iran - as well as domestic discontent in the aftermath of the "Arab Spring" - has prompted Gulf Co-operation Council (GCC) members to significantly raise their spending. "The West still spent over half of global defence outlays in 2013 (but) this is down from two thirds in 2010," IISS Director-General John Chipman told a press briefing. "Emerging economies continue to ramp up their defence spending levels."

Copyright Reuters, 2014