MOSCOW: Troops from Ukraine were involved in Georgia's bid in August last year to regain control of its rebel South Ossetia region that led to a war with Russia, Russian prosecutors said Monday.

"Members of the regular Ukrainian armed forces took part in the armed aggression by Georgian forces against South Ossetia," the investigative committee of Russian prosecutors said in a statement.

It did not give numbers but said that 200 members of the Ukrainian nationalist movement UNA-UNSO were also involved in the operation.

The statement risks further worsening relations between Russia and the pro-Western authorities in Ukraine which have plunged to an all-time low over the last months.

The war began late on August 7 last year when Georgian forces launched an assault on South Ossetia following days of escalating violence.

Russia's counter-attack drove Georgian forces out of the rebel region and pushed them back deep into Georgian territory.

Russia has previously accused Ukraine of shipping arms to Georgia and accused Ukrainian irregulars of taking part in the war. But this appears to be the first time it has accused the regular armed forces of involvement.