Fighting between heavily armed gangs is increasing in the oil rich Delta region. Many of the armed gangs were formed, and armed, last year by politicians competing for provincial office. The political gangs were used to intimidate voters who supported rivals. Voting is often along tribal lines, so the political gangs are tribal as well. However, some of the political gangs did not receive the promised cash payments after the election, refused to turn in their weapons, and went into business as criminal gangs.