Angola returned to all-out war in December 1998, the fourth period of open warfare in living memory. The human cost since fighting resumed is impossible to determine with precision, but the United Nations estimates that nearly one million people have become internally displaced persons because of the renewed conflict, 10 percent of Angola's population. This return to war also represented the end of the uneasy peace process that began with the Lusaka Protocol in Zambia in November 1994. The Lusaka Protocol provided for a cease-fire, the integration of UNITA generals into the government's armed forces (which were to become nonpartisan and civilian controlled), demobilization (later amended to demilitarization) under U.N. supervision, the repatriation of mercenaries, the incorporation of UNITA troops into the Angolan National Police under the Interior Ministry, and the prohibition of any other police or surveillance organization. As a backdrop to the protocol, a Security Council embargo on arms and oil transfers to UNITA had been in place since 1993, while both the government and UNITA had agreed to halt new arms acquisitions as part of the accords. But the embargo on UNITA was not enforced, and both sides openly continued major arms purchases throughout the process.