Three people were killed and 11 injured Friday in a bomb blast in the capital of the Republic of Dagestan, Makhachkala, in Russia, the Russian TV reported. It quoted Russian security sources as saying the blast occured when a Russian military vehicle was searching for explosives and ammunition in the region. The Russian security forces chased a number of people suspected of being the bomb attack, but they managed to escape, added the sources. The suspects left a car behind which contained explosives and ammunition, they said. Dagestan had in the last years turned into a source of tension. It witnessed scores of bomb attacks by extremists.