MOSCOW, June 9 (RIA Novosti) - Russia's federal budget deficit increased in May by 140.9 billion rubles ($4.5 billion), to reach 511 billion rubles ($16.3 billion) for the first five months of the year, the Finance Ministry said Tuesday.

The budget deficit stood at 3.6% of GDP for the first five months of the year, the ministry said.

Budget revenue in January-May 2009 totaled 2.640 trillion rubles ($84.4 billion) or 39.3% of the budget revenue plan for the year, while expenditure stood at 3.151 trillion rubles ($100.7 billion) or 32.2% of the budget's specified spending, the statement said.

Russia's Reserve Fund shrank by 11.9% to 3.127 trillion rubles ($100.95 billion), and the National Prosperity Fund declined 3% to 2.784 trillion rubles ($89.86 billion) in May.

The Reserve Fund was set up to cushion the federal budget against a fall in oil prices, and the National Prosperity Fund is designed to help the government carry out pension reforms.