MOSCOW (AFP) - A top officer was among eleven people including eight Russian soldiers killed in a car bombing in the Georgian rebel city of Tskhinvali, Russian media reported Saturday, amid conflicting reports on the incident. The death of Colonel Ivan Petrik, head of the Russian military's joint staff for the South Ossetia conflict zone, was first reported by Kommersant newspaper and confirmed to Interfax by a spokesman for Russian land forces, Ivan Konashenkov. South Ossetia, a rebel region of Georgia backed by Russia, was at the centre of an August war between Georgia and Russia. Kommersant said the car had been brought to the Russian military base in Tskhinvali under the direction of Russian military personnel after local militia found it abandoned in a buffer zone around South Ossetia. The report contradicted earlier claims that the car had been seized from Georgian citizens. Kommersant predicted that the blast might be used to justify keeping Russian troops in the buffer zone around South Ossetia beyond an Oct 10 deadline to withdraw to pre-conflict positions, under a European-brokered peace deal. Meanwhile, Georgian secret services were behind a car bomb blast in the breakaway region of South Ossetia, Russian investigators said on Saturday, quoted by news agencies. "The investigative group carrying out a preliminary examination has every reason to believe the explosion in Tskhinvali was arranged by Georgian secret services in order to destabilise the situation," a spokesman for the prosecutor's investigative department, Vladimir Markin, was quoted by RIA Novosti and Interfax as saying. While, Georgia on Saturday denied any involvement in a deadly car bomb blast in South Ossetia region following an accusation by Russian prosecutors. "How could we have done this? How could we possibly have known that the Ossetians were going to take this car and then bring it to the headquarters" of Russian forces in South Ossetia, Georgian interior ministry spokesman Shota Utiashvili told AFP. "The headquarters of the Russian forces in South Ossetia is one of the most well-protected facilities in the region, added Utiashvili. "We don't have access to Tskhinvali. We don't have access to the buffer zone. How could Georgia have been behind this?" he said, referring to a buffer zone that Russia is patrolling around South Ossetia.