DESPITE a recession that reduced global arms sales last year, the United States expanded its role as the world's leading weapons supplier, increasing its share to more than two-thirds of all foreign armaments deals, according to a new congressional study.

The US signed weapons deals valued at $US37.8 billion ($47.8 billion) in 2008 - 68.4 per cent of international sales - up from $US25.4 billion the previous year.

The growth was particularly noticeable against worldwide trends. The value of global arms sales in 2008 was $US55.2 billion, a drop of 7.6 per cent from 2007 and the lowest total for international weapons agreements since 2005.

The increase in US weapons sales around the world ''was attributable not only to major new orders from clients in the near-east and in Asia, but also to the continuation of significant equipment and support services contracts with a broad-based number of US clients globally'', according to the study.

The annual report was produced by the nonpartisan Congressional Research Service, a division of the Library of Congress. Regarded as the most detailed collection of unclassified global arms sales data available to the general public, it was delivered to the US House and Senate on Friday, ready for members' return from the Labor Day recess.