* Head of GRU military intelligence says situation 'tense'

* Says NATO members, Ukraine, Israel arming Tbilisi

MOSCOW, Nov 5 (Reuters) - The head of Russia's powerful military intelligence agency said on Thursday that Georgia might again attack South Ossetia, the pro-Moscow region over which the two countries fought a war last year.

Alexander Shlyakhturov, who in April took over command of the GRU -- the Russian acronym for Russia's Chief Intelligence Agency -- said the situation was strained and accused NATO of continuing to supply arms to Georgia.

"The situation with Georgia remains tense because the current Georgian authorities do not just refuse to recognise the sovereignty of Abkhazia and South Ossetia, but are trying in every way to return these countries...to their jurisdiction," he said in a rare interview with state news agency ITAR-TASS.

"You have to add to this the unpredictability of attempts by the Georgian leadership, headed by (President Mikheil) Saakashvili, which may give in to temptation to use force to tame these obstinate republics as they did last year," he said.

"We do not rule out such a development."

South Ossetia and Abkhazia broke away from Georgian government control in the early 1990s. Russia recognised both as independent states after last year's five-day war, when its forces repelled a Georgian attack on South Ossetia.

But only two other countries, Nicaragua and Venezuela, have followed Russia's lead, and the rest of the world regards the two regions as part of Georgia.

Shlyakhturov said that "new NATO members" in Eastern Europe were supplying small arms and munitions to Georgia while Israel was providing drones and Ukraine was delivering heavy artillery and anti-aircraft systems.

The GRU is Russia's biggest spy agency, with agents spread across the globe and thousands of special forces troops inside Russia. The spy service, created in 1918 under revolutionary leader Leon Trotsky, is controlled by the military general staff and reports directly to the president.

(Writing by Conor Humphries; Editing by Mark Trevelyan)

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