'In 2007, he was sent to Dagestan with instructions to bring the local gangs under control, to ensure their funding from abroad and arrange for channels for militants to infiltrate into the republic,' an official said.

In the republic's capital, Makhachkala, gunmen killed a police officer early Monday. 'The criminals knocked at the door where the police officer lived and shot him five times,' a police spokesman said.

Militant attacks on troops, police and other officials have been reported almost daily in Dagestan and Russia's other mainly Muslim North Caucasus republics in recent months.

On Aug 17, Ingushetia was rocked by a suicide bombing which killed at least 24 police officers and injured 136 others.

Following the blast, Ingushetia's president, Yunus-Bek Yevkurov, returned to the republic after spending two months in Moscow recovering from serious injuries sustained in a car bomb attack on his motorcade earlier.