Russian security forces have launched a massive manhunt for the killers of six men in a southern region not far from the venue of the Winter Olympics next month.

The bodies with gunshot injures were found on Wednesday in four cars parked in two separate districts of Stavropol Region, about 300 km from Sochi, where Russia will host Olympic Games in four weeks’ time.

Explosive devices had been placed near two of the cars, and one of them went off when police approached the vehicle. No one was hurt.

Police stopped short of qualifying the murders as an act of terrorism, but experts had no doubt about it.

“Setting up explosives near corpses is trademark tactics of terrorists,” said Valery Malevanny, former security service officer.

A spokesman for Russia’s Investigation Committee said that Federal Security Service officers had joined the investigation, even though no motive had yet been determined.

Media reports said police were looking for three young men from neighbouring Kabardino-Balkaria, one of several regions in North Caucasus hit by low-intensity insurgency.

Wednesday’s incident took place a day after Russia launched an unprecedented security operation for the coming Olympics, deploying almost 100,000 police, armed forces and security personnel in and around Sochi.

Experts voiced concern that the extraordinary security effort could leave other regions of Russia vulnerable to terrorist attacks.

Less than two weeks ago twin suicide bombings killed 34 and injured more than 60 people in Volgograd, 400 km northeast of Stavropol Region.

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