Russia hit by suspected suicide attack

At least 12 people have been killed in a suspected suicide attack in Russia's North Caucasus.

The coordinated attack in the town of Kizlyar in Dagestan, neighbouring Chechnya, is the latest outbreak in a surge of violence in the Caucasus that is challenging the Kremlin a decade after a war against Chechen separatists.

A suicide bomber dressed in a police uniform set off the second of two blasts in Kizlyar, which killed the town's police chief and several other officers.

The bomber pushed his way into a crowd of police and onlookers drawn to the site by a car bomb explosion, a common tactic of insurgents in the region, who have been attacking law enforcement authorities almost daily.

A police official said a black four-wheel-drive Niva vehicle had exploded after traffic police tried to stop it, indicating a suicide bomber had been behind the wheel.

Footage showed two gutted cars and a deep crater on a debris-strewn street lined by bare trees, and a red brick schoolhouse with its windows blown out and roof partly ripped off. Reports said there were no children in the school.

The bombings came 48 hours after Moscow was hit by two morning rush-hour blasts that killed 39, its bloodiest attack in six years.

Russian authorities have blamed female suicide bombers with connections to the North Caucasus.