Moscow: Russian authorities on Thursday vowed to strike back after a bomb blast the night before killed seven people and wounded dozens in the southern city of Stavropol minutes before a Chechen dance concert.
A bomb packed with steel pellets hidden in a juice carton went off near a cultural centre as locals were gathering for the performance of a renowned Chechen folk group.
By Thursday morning, the death toll had risen to seven, including a 12-year-old girl, and 33 people remained hospitalized, many in critical condition, officials said.
So far no group has claimed responsibility for the blast but officials said those who did not want peace in the Caucasus would not succeed.
Stavropol, which lies on the northern edge of the Caucasus, has until now rarely seen the bloody attacks that characterize the simmering guerrilla war between Russian forces and separatist rebels.
"This is an audacious provocation," regional governor Valery Gayevsky said in comments released by his administration.
"Someone wants to shake loose the friendly relations between the peoples and republics. These forces do not want peace in the Caucasus. But we will put them in their place," he said.
Chechnya`s strongman leader Ramzan Kadyrov blamed "Russia`s enemies" for the blast.
Russia`s top investigator Alexander Bastrykin left for Stavropol to personally oversee the investigation.
Russia is battling a Muslim insurgency in the North Caucasus and terror attacks in the republics of Chechnya, Ingushetia and Dagestan are a near-daily occurrence.
Yekaterina Danilova, an official with the regional investigative committee, said investigators were considering several theories, including terrorism and attemps to stir up ethnic hatred in the predominantly Russian city.
Dolgova said 41 people were injured in the blast.
"We`ve worked all night," said Danilova, telling AFP that nearly 70 people have already been questioned in connection with the explosion.
In March, Russia was shaken to the core when two female suicide bombers, both from the North Caucasus region of Dagestan, killed 40 people in a pair of coordinated attacks on the Moscow metro during the morning rush hour.
President Dmitry Medvedev has said the unrest in the Caucasus is Russia`s single most serious domestic problem.
Human rights advocates say the controversial tactics of Russian troops in the North Caucasus contribute to instability in the region.
The Kremlin attempted to strengthen its hold in the region in January by appointing a powerful new envoy responsible for the North Caucasus, businessman Alexander Khloponin.
Medvedev called for Khloponin, who was also made deputy prime-minister, to concentrate on improving the economy in the region, where corruption and unemployment are rife.
Islamist leader Doku Umarov, head of the so-called "Caucasus Emirate," vowed in February that rebels would move the target of their attacks from the Caucasus to Russia`s heartland.