A home-made explosive device went off on the roadside in the city of Malgobek in Ingushetia when a police patrol car was passing by. Three policemen were in the car. None of the policemen was injured, Itar-Tass quoted a representative of the republic's law enforcement bodies as saying. The incident occurred in Promyshlennaya Street at about 03.00 Moscow time, the source specified. According to the available information, the explosive device was filled with shrapnel. Its power was equivalent to about seven kilograms of TNT. Investigation is underway.