A car bomb has killed at least three people in the southern Russian city of Pyatigorsk near the violence-plagued Caucasus on Friday, according to the Itar-Tass news agency citing a security source.
The agency said the car exploded near a shopping centre, while Interfax reported it badly damaged a traffic police building.
No group has yet claimed responsibility for the bombing. Several armed Islamist groups are active in the north Caucasus region and have been held responsible for previous attacks against police and military targets.
The bombing comes at a delicate time for Russian authorities, who are preparing to host the 2014 Winter Olympics in Sochi, which lies on the north-western edge of the Caucasus mountain range around 250 kilometres west of Pyatigorsk. President Vladimir Putin has demanded maximum security of law enforcement agencies in the troubled region. In October, six people died when a suicide bomber struck on a bus in Volgograd, which is located around 670 kilometres north-east of Sochi.