World military spending grew 45 percent in the past decade, with the United States accounting for nearly half of all expenditure, the Stockholm International Peace Research Institute (SIPRI) said Monday.

Military spending grew six percent last year alone, according to SIPRI's annual report.

In 2007, 1,339 billion dollars (851 billion euros) was spent on arms and other military expenditure, corresponding to 2.5 percent of global gross domestic product, or GDP -- or 202 dollars for each of the world's 6.6 billion people.

The United States spends by far the most towards military aims, dishing out 547 billion dollars last year, or 45 percent of global expenditure.

Britain, China, France and Japan, the next in line of big spenders, lag far behind, accounting for just four to five percent of world military costs each.

"The factors driving increases in world military spending include countries' foreign policy objectives, real or perceived threats, armed conflict and policies to contribute to multilateral peacekeeping operations, combined with the availability of economic resources," the SIPRI report said.

The increase is both "excessive and obscene," Jayantha Dhanapala, a SIPRI member formerly in charge of disarmament affairs at the United Nations, told reporters in Stockholm, where the annual report was presented.

Registering the greatest regional growth was Eastern Europe, which saw its military spending skyrocket 162 percent between 1998 and 2007 and 15 percent from 2006 to 2007.

Russia, whose expenditure ballooned 13 percent last year, was responsible for 86 percent of the growth in the region, according to SIPRI.

North America meanwhile saw its military spending swell 65 percent, largely pulled by the United States, which has seen its costs grow 59 percent since the September 11, 2001 attacks in New York and Washington.

"By 2007, US spending was higher than at any time since World War II," the SIPRI report said.

In the past decade, the Middle East has boosted military expenditure by 62 percent, South Asia by 57 percent and Africa and East Asia by 51 percent each.

Western Europe was the region with the least military spending growth at just six percent, followed by Central America at 14 percent.

At a national level, "China has increased its military spending threefold in real terms during the past decade," SIPRI said, adding however that "due to its rapid economic growth, the economic burden of military spending is still moderate, at 2.1 percent of GDP."

As a direct result of the increased military outlay, sales by the world's 100 leading arms producing companies (excluding in China) jumped nearly nine percent in 2006 compared to the year before to 315 billion dollars, SIPRI said.

Sixty-three of the 100 top weapons firms are based in the United States and Western Europe, accounting alone for 292.3 billion dollars in sales in 2006, the last year for which SIPRI has numbers.

In its report, the group also said 14 major armed conflicts raged around the world last year -- the same number as in 2006. In 2001, there were 20, SIPRI said.

"A new type of conflict is emerging and we are seeing a fragmentation of violence," in places such as Iraq and Sudan's Darfur province, SIPRI researcher Ekaterina Stepanova told the Stockholm press conference.

This non-state violence "may have devastating consequences for civilians. All the actors tend to be opportunistic and may change sides," she added.

On an upbeat note, SIPRI chief Bates Gill meanwhile said both candidates in this year's US presidential election could help pave the way for "the most promising opportunities to see real progress in the nuclear arms control that we have seen in the last 10 years."