Reuters reports:

Russia's volatile North Caucasus experienced one of its worst eruptions of violence in months with at least nine people killed in a series of attacks across the region, officials said on Friday.

The Kremlin is struggling to contain a mix of Islamist insurgents, separatist rebels and organized crime in the North Caucasus, even though a separatist rebellion in one of the region's hotspots, Chechnya, has largely been quelled.

The latest violence included a blast in the Ingushetia region that killed four people, a remote-controlled bomb in neighboring Dagestan that killed one man and a rebel raid in Chechnya that killed at least three.

Former Russian President Vladimir Putin vowed when he took office eight years ago to end violence in the North Caucasus, home to a collection of impoverished and mainly Muslim mountain tribes who have periodically rebelled against Moscow's rule.

Though he succeeded in restoring control over most of Chechnya, when he handed the president over to his protege Dmitry Medvedev last month the North Caucasus remained a source of instability.

WAVE OF VIOLENCE

Officials on Friday reported the following attacks over a two-day period in the North Caucasus:

* In Nazran, the biggest city in the Ingushetia region, four people were killed on Friday in an explosion that destroyed a building, emergency services said. Police said they suspected an accidental gas blast.

But a local interior ministry source told Reuters the explosion was deliberate. The destroyed building housed a liquor shop. The owner had previously received threats from Islamist insurgents who demanded he stop selling alcohol, the source said.

"There was a blast and black smoke pouring out," said 39-year-old Nazran resident Ruslan, who was passing the building at the time of the incident. "People were running away in panic ... some were covered in blood."

* In next-door Chechnya late on Thursday, at least 25 armed rebels raided the village of Benoi-Vedeno, killing three locals and setting several houses on fire, Russian news agencies quoted officials as saying.

An internet site with ties to the separatist movement, www.kavkazcenter.com, said the rebels had killed 11 armed men linked to Ramzan Kadyrov, Chechnya's pro-Moscow president. It denied the rebels killed any local residents.

It was not immediately possible to independently verify accounts of the raid.

* In Dagestan, a remote-controlled bomb killed a jogger in a park in the capital, Makhachkala, local police said. A passerby was injured and taken to hospital. Police said the explosive device was packed with shrapnel.

Russian television pictures from the scene showed a pool of blood on a pavement. The blast happened near some administrative buildings.

* Security forces killed an armed insurgent in Bayram Aul, a settlement to the north of Makhachkala, Interfax news agency quoted a source in the region's interior ministry as saying. The agency said there had been a firefight lasting two hours.