London's International Institute for Strategic Studies said on Wednesday the United States remains by far the world's pre-eminent military power, spending some $600 billion Last year, nearly 38 percent of the global total.
The report estimated that Saudi Arabia was spending $59.6 billion - a figure researchers said was extremely conservative - pushing it above Britain at $57 billion or France at $52.4 billion. Saudi spending increased 8.6 percent in the 2012-13 period, it said.
Of the top global spenders by percentage of gross domestic product, the vast majority were in the Middle East - Oman, Saudi Arabia, Iraq, Bahrain, Libya, Algeria, Yemen and Jordan.
Overall global military spending probably fell marginally in 2013, it said, but increased dramatically in Asia and the Middle East. China's defense expenditure had climbed by about 40 percent since 2010, surging to an estimated $112 billion.
The report also blames China's growing military budget for sparking a wider Asian arms race, with Japan, South Korea, Vietnam and others also surging their spending.
Despite a U.S. "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, the report adds, Persian Gulf Arab states’ worries over domestic discontent in the aftermath of the "Arab Spring" has prompted Persian Gulf Cooperation Council (PGCC) members to significantly raise their spending on military hardware.
"The West still spent over half of global defense 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 defense spending levels."
Russia increased its defense spending to some $68.2 billion, up 30 percent from 2010 and now accounting for roughly a quarter of all European defense expenditure.
If Chinese military spending continues to increase at the current pace, IISS researchers estimate it may overtake that of the United States sometime in the 2030s. But it would likely take longer to match Washington's overall military capabilities, the IISS said.
HH/MB