(Reuters) - Arms deliveries to Syria surged almost 600 percent from 2007 to 2011 compared with the previous five years, a leading think tank said on Monday, with Russia supplying the bulk of the country´s weapons.

The report underlined how Moscow has continued to supply Syria with firepower while the United States, European Union and others have imposed arms embargoes in response to Syrian President Bashar al- Assad´s bloody crackdown on unrest.

World powers have been unable to stop more than a year of bloodshed in Syria, a country that sits on the fault lines of several regional and ethnic conflicts. Recent army gains against rebel positions have not succeeded in quelling the violence and no negotiated settlement is in sight.

The Stockholm International Peace Research Institute (SIPRI) said Russia had supplied 78 percent of Syria´s weapons imports during the past five years, contributing to a 580 percent increase in the volume of arms imports by Syria.

"The transfer of arms to states affected by the Arab Spring has provoked public and parliamentary debate in a number of supplier states," said Mark Bromley, senior researcher with the SIPRI Arms Transfers Programme.

"However, the impact of these debates on states´ arms export policies has, up to now, been limited."

Global arms transfers in the period rose by almost a quarter. The five largest importers were all Asian states, with Asia and Oceania accounting for 44 percent of purchases, followed by Europe at 19 percent, the Middle East at 17 percent, the Americas 11 percent and Africa 9 percent.

India was the world´s single largest importer of arms, accounting for 10 percent of the total, followed by South Korea, Pakistan, China and Singapore. China, the largest recipient of arms during the previous 2002-2006 period, fell in the rankings due to increased domestic production.

SIPRI uses a system which attempts to measure volume rather than the financial value of weapons transfers. It does this by using a methodology which intends instead to represent the transfer of military resources. (Reporting by Mia Shanley; Editing by Mark Heinrich) (© Thomson Reuters 2012. 03/19/12)