* Russian sales boosted by Kremlin military modernisation
* Bucks slowdown caused by U.S. withdrawals, Europe crisis
* SIPRI expects Western sales to grow on Russian fears
STOCKHOLM, Dec 15 (Reuters) - Russian arms makers' sales soared 20 percent in 2013, bucking a slowdown in other countries' industries, largely thanks to a Kremlin push to modernise its military, the SIPRI think tank said on Monday.
Russia's figures were strong enough to slow a three-year decline in global arms sales caused mainly by Washington's withdrawal from Iraq and Afghanistan and the economic crisis in Europe, SIPRI researcher Siemon Wezeman said.
"The remarkable increases in Russian companies' arms sales in both 2012 and 2013 are in large part due to uninterrupted investments in military procurement by the Russian Government during the 2000's," Wezeman added.
Russian President Vladimir Putin has increased defence spending since coming to power in 2000, seeing rebuilding of the armed forces as a central part of his attempts to restore Russia's position on the world stage.
The Stockholm International Peace Research Institute's (SIPRI's) widely read survey of the world's 100 biggest arms makers, excluding Chinese firms, showed combined turnover down 2 percent to $402 billion in 2013, slower than the 4 percent decline seen in 2012.
Sales by some of the world's biggest suppliers in the United States and Canada continued to fall while the picture was mixed in Western Europe with sales up in France, steady in Britain and down in Spain and Italy.
Wezeman told Reuters that some of the recent declines in Europe had been caused by a perception of a lower military threat.
"In 2014, the threat perception has started to change. Russian actions have woken up many European countries ... That will probably translate into additional procurement from 2015," he added.
Russia annexed Ukraine's Crimea region in March and Western powers have accused it of backing and arming separatist rebels in Ukraine's east -- a charge dismissed by Moscow.
Russia's Tactical Missiles Corporation showed the country's strongest growth, at 118 percent, according to the survey.
Topping the global rankings were Lockheed Martin followed by Boeing, both from the United States, and in third place Britain's BAE Systems.
SIPRI recorded strong growth in some suppliers in emerging markets, including South Korea, Brazil and Turkey. China-based companies are not included because of what the think tank says is a lack of reliable data. (Reporting by Anna Ringstrom; Editing by Daniel Dickson and Andrew Heavens)