At least five people were killed and 20 injured today when a car exploded near the central market of a major city in Russia’s restive North Caucasus region, officials said.

A bomb exploded beneath a train in Russia’s violence-plagued Dagestan region today, killing one person and injuring four others, police said.

Anti-tank grenades were fired overnight at a Russian security services building in the southern republic of Dagestan, police said today. No one was injured.

They lived in the same apartment in Chechnya, worked in the same market and possibly died within moments of each other on separate airliners that crashed in Russia last week.

Two Russian police officers have been killed when a car bomb exploded near the border with Chechnya.