“Officers of the patrol and checkpoint service of the region’s interior ministry were returning in jeeps and trucks from a post where they had worked a shift,” said the secretary of the region’s security council, Akhmed Kotiyev, quoted by the RIA Novosti news agency.

“As the convoy passed close to the village of Dattykh, a homemade exposive device went off, placed on the edge of the road.”

The unidentified attackers then opened fire on the police with guns and grenade launchers, Kotiyev said.

“According to the information we have at the moment, four officers died and two were wounded and hospitalised.”

Interfax news agency quoted a law enforcement source as saying that one policemen later died from wounds received in the attack in central Ingushetia but there was no official confirmation.

Around 10 rebels took part in the attack, first using a remote-controlled device to trigger an explosion close to the vehicle in front, then opening fire on the convoy, the source said.

Russia is fighting a simmering Islamist insurgency in the Caucasus, mostly in Dagestan and Ingushetia, which see regular attacks that officials blame on militants seeking to establish an Islamic state across the Russian Caucasus.