An explosion Friday in the volatile Russian Caucasus region of Dagestan killed one policeman and wounded three others, law enforcement officials said.
The explosion occurred at Buynaksk, some 40 kilometres (25 miles) southwest of the republic's capital Makhachkala, a spokesman for the local Investigative Committee, which handles serious crimes, told the Interfax news agency.
"According to preliminary information, one policeman was killed and three others wounded," he said without providing additional details.
The North Caucasus, the southwest Russian region where Dagestan is located, sees frequent violence that officials blame on militants seeking to establish an Islamic state across the impoverished territory.
Dagestan is currently the most unstable region in the Northern Caucasus, with rebels staging attacks against the pro-Kremlin local authorities almost every day.