An explosion has hit the centre of the southern Russian city of Vladikavkaz, near the war-torn republic of Chechnya. At least one person was killed and several Russian interior ministry troops were injured. Reports said the troops were driving past in a military vehicle when the blast happened. It is not known who was behind the explosion, but the region has seen many attacks by Chechen fighters in recent years. The blast is said to have taken place at about 1720 local time (1420GMT) near a bank, about 100 metres (330 feet) from the central city market. Explosives are thought to have been packed into a car, which was torn apart by the blast. Witnesses saw three other vehicles on fire. A woman pedestrian was killed, and there are reports that one serviceman also died. Heavy smoke filled the area, and glass was blown out in some of the nearby buildings. Police have sealed off the area, and emergency services are on the scene. **Previous attack*** It seems likely that the finger of suspicion of the latest blast will be pointed at Chechen fighters. Vladikavkaz is the capital of the North Ossetia region bordering Chechnya. The fighting in Chechnya occasionally spills into neighbouring areas, which have also been the site of shootings and bombings related either to the war or to local crime groups. A bomb attack on the same market in 1999 killed 55 people and injured another 168. Another bomb in April 2002 killed seven people and injured at least 39 others.