Land disputes continue to cause much of the unrest in the three years since the end of the military dictatorship. The lad ownership laws encourage communal ownership of land, and a lot of land is under long term lease from one tribe to another. A common cause of dispute is the sudden refusal of one tribe to pay rent to another tribe on land it has been occupying for a century or more. Much land is also held by feudal chiefs. Population growth, and the inability to buy and sell much land is causing more unrest and violence.