The Nigerian government and multinational oil companies should take immediate measures to prevent further violence and abuses around Warri in the oil-rich Niger delta, Human Rights Watch today said in letters to President Olusegun Obasanjo and the managing directors of three companies...Human Rights Watch appealed to the main companies operating in the area - ChevronTexaco, Royal Dutch/Shell and TotalFinaElf - to publicly urge the Nigerian government to restore security in a manner that respects due process and fundamental human rights, and that is not disproportionate to the threat.