Global military spending fell for a second consecutive year in 2013, mainly on the back of cuts in the US, a Swedish-based peace research institute says.
Other top spenders such as China, Russia and Saudi Arabia increased their outlays, the Stockholm International Peace Research Institute (SIPRI) said on Monday.
SIPRI estimated that global military expenditure totalled $US1.75 trillion ($A1.87 trillion) in 2013, down 1.9 per cent from 2012.
The US remained the world's largest military spender on $US640 billion, down 7.8 per cent year-on-year, SIPRI said, citing US withdrawals from Afghanistan and Iraq as well as budget cuts approved by the US Congress.
The size of the US expenditures were equal to that of the nine other top spenders combined. SIPRI estimated that if the US cuts were not counted, global spending increased by 1.8 per cent in 2013.
Second-placed China increased its spending 7.4 per cent year-on-year to an estimated $US188 billion while third-placed Russia's spending rose by almost 5 per cent to $US87.8 billion.
Saudi Arabia spent $US67 billion in 2013, up 14 per cent year-on-year, moving it from seventh to fourth place among global spenders.
Rounding off the list of top 10 spenders were France, Britain, Germany, Japan, India and South Korea.
Regional differences in spending continued. Spending declined in Australia, North America, and Western and Central Europe as austerity measures continued, but grew in Africa, Asia, Eastern Europe, Latin America and the Middle East.
"In some cases it is the natural result of economic growth or a response to genuine security needs," Sam Perlo-Freeman, head of SIPRI's military expenditure program, said of the increase.
"In other cases it represents a squandering of natural resource revenues, the dominance of autocratic regimes or emerging regional arms races," he added.
China's higher spending was cited as the main reason for the 3.6 per cent increase in Asia. Expenditures were also up in the Philippines and Vietnam, who had territorial conflicts with China. Japan halted its defence budget cuts over concerns with China's rising military clout, SIPRI said.
In the Middle East, military spending rose 4 per cent year-on-year.
Large increases were reported in Bahrain and Iraq. Statistics were lacking for several countries including Iran, Syria, and the United Arab Emirates.
The region with the highest increase in spending in 2013 was Africa - up 8.3 per cent year-on-year, SIPRI said.
Africa's top spenders, Algeria and Angola, used oil and gas revenue to increase military expenditures.
The two were among 23 countries - others included Afghanistan, Argentina, Armenia, Azerbaijan, China, Ghana, Paraguay, Russia and Saudi Arabia - that have doubled their military spending since 2004.
The 23 shared several traits including strong economic growth, high oil or gas revenues, and internal or regional conflict.
SIPRI said its figures include salaries, costs for operations, purchases of arms and equipment as well as research and development.
The Swedish parliament created SIPRI as an independent foundation in 1966.
