A bomb killed four policemen in the southern Russian province of Dagestan today during their morning exercises in a school yard, a police spokesman said.
Dagestan borders Chechnya, where Russian soldiers have battled rebels in two wars since 1994. Over the last few years the violence has spilled over into neighbouring provinces.
The bomb exploded in the town of Kizilyurt, about 50 kilometres from the capital Makhachkala, the police spokesman said.
Russian news agencies said six policemen had been taken to hospital. No further details were immediately available.