In the 1986 elections, the National Umma Party lost several seats to the Nuba Mountains General Union and to the Sudan National Party, due to the reduced level of support from the Nuba Mountains region. There is reason to believe that attacks by the government-supported militia, the Popular Defense Force (PDF), on several Nuba villages were meant to be in retaliation for this drop in support, which was seen as signaling increased support of the SPLA. The PDF attacks were particularly violent, and have been cited as examples of crimes against humanity that took place during the Second Sudanese Civil War