By Darya Korsunskaya and Alexander Marrow

(Reuters) -Russia recorded a marginal budget surplus in May, enabling it to slightly reduce its deficit for the first five months of the year to 3.41 trillion roubles ($41.9 billion), the finance ministry said on Tuesday, as monthly spending slowed.

In January-May 2022 Russia posted a surplus of 1.59 trillion roubles, but outlays to support its military campaign in Ukraine and Western sanctions on its oil and gas exports have since depleted government coffers. This year's deficit is already 117% of the annual plan.

Soaring defence spending has kept Russia's industrial sector ticking along, driving forecasts for economic growth this year and helping Moscow to continue its military campaign in Ukraine.

The finance ministry stopped publishing individual monthly budget fulfilment data last year, but based on Tuesday's figures, Russia posted a surplus in May of 13 billion roubles.

That compares with a 1-trillion-rouble deficit in April. Monthly spending in May was its lowest this year, 1.1 trillion roubles lower than in April, but to meet this year's overall 29.1-trillion-rouble expenditure target, spending will have to fall further.

Meanwhile, non-oil-and-gas revenues for January-May were 9.1% higher than the same period last year.

But Moscow's crucial oil and gas revenues were 49.6% lower year-on-year in the first five months, which the finance ministry put down to lower prices for Urals crude and lower natural gas export volumes.

Spending was 26.5% higher year-on-year in that period, the preliminary data showed, while income was down 18.5%.

Finance Minister Anton Siluanov has repeatedly said Russia's budget deficit this year would be no more than 2% of GDP, although most analysts disagree. The International Monetary Fund is among those expecting Russia to see a sharply wider budget deficit this year.

The finance ministry on Tuesday said it expects tax revenues from the oil sector to recover in the second half of the year.

The fall in revenues has forced Moscow to start selling international reserves to help cover the deficit, while analysts have suggested raising taxes is another option.

Russia has spent almost 440 billion roubles covering the deficit from the National Wealth Fund (NWF) so far this year.

($1 = 81.3705 roubles)