MAKHACHKALA - Suicide bombers killed 12 people and wounded 110 in attacks on a police post on the outskirts of the capital of Russia's Dagestan region, local investigators and law enforcement sources said on Friday.

The attacks outside Makhachkala late on Thursday were the deadliest in months, undermining efforts by Russian security forces to contain an Islamist insurgency in the North Caucasus near Sochi, where Russia will host the Winter Olympics in 2014.

More than a decade after federal troops toppled an Islamist government in Chechnya, also in the North Caucasus, security forces are fighting militants whose ranks are swollen by anger at poverty, clan feuds and pervasive corruption.

The first suicide bomber detonated a bomb when police stopped a vehicle to check documents, a statement by the National Anti-Terrorist Committee said.

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