The conflict in Sierra Leone dates from March 1991 when fighters of the Revolutionary United Front (RUF) launched a war from the east of the country near the border with Liberia to overthrow the government. With the support of the Military Observer Group (ECOMOG) of the Economic Community of West African States (ECOWAS) Sierra Leone's army tried at first to defend the government but, the following year, the army itself overthrew the government.

Despite the change of power, the RUF continued its attacks. In February 1995, the United Nations Secretary-General appointed a Special Envoy, Mr. Berhanu Dinka (Ethiopia). He worked in collaboration with the Organization of African Unity (OAU) and ECOWAS to try to negotiate a settlement to the conflict and return the country to civilian rule.

Parliamentary and presidential elections were held in February 1996, and the army relinquished power to the winner, Alhaji Dr. Ahmed Tejan Kabbah. The RUF, however, did not participate in the elections and would not recognise the results. The conflict continued.

Special Envoy Dinka assisted in negotiating a peace agreement, in November 1996, between the Government and RUF known as the Abidjan Accord. The agreement was derailed by another military coup d'état in May 1997. This time the army joined forces with the RUF and formed a ruling junta. President Kabbah and his government went into exile in neighbouring Guinea.

A new Special Envoy, Mr. Francis G. Okelo (Uganda) and other representatives of the international community tried, but failed, to persuade the junta to step down. The Security Council imposed an oil and arms embargo on 8 October 1997 and authorized ECOWAS to ensure its implementation using ECOMOG troops.

On 23 October, the ECOWAS Committee of Five on Sierra Leone and a delegation representing the chairman of the junta held talks at Conakry and signed a peace plan which, among other things, called for a ceasefire to be monitored by ECOMOG and -- if approved by the UN Security Council -- assisted by UN military observers. On 5 November, President Kabbah issued a statement indicating his acceptance of the agreement, and stated his Government's willingness to cooperate with ECOWAS, ECOMOG, the United Nations and UNHCR in the implementation of their respective roles. Although the junta publicly committed itself to implementing the agreement, it subsequently criticized key provisions and raised a number of issues, with the result that the agreement was never implemented.

In February 1998, ECOMOG, responding to an attack by rebel/army junta forces, launched a military attack that led to the collapse of the junta and its expulsion from Freetown. On 10 March, President Kabbah was returned to office. The Security Council terminated the oil and arms embargo and strengthened the office of the Special Envoy to include UN military liaison officers and security advisory personnel.

On June 1998, the Security Council established the United Nations Observer Mission in Sierra Leone (UNOMSIL) for an initial period of six months. The Secretary-General named Special Envoy Okelo as his Special Representative and Chief of Mission. The mission monitored and advised efforts to disarm combatants and restructure the nation's security forces. Unarmed UNOMSIL teams, under the protection of ECOMOG, documented reports of on-going atrocities and human rights abuses committed against civilians.

Fighting continued with the rebel alliance gaining control of more than half the country. In December 1998 the alliance began an offensive to retake Freetown and in January overran most of the city. All UNOMSIL personnel were evacuated. The Special Representative and the Chief Military Observer continued performing their duties, maintaining close contact with all parties to the conflict and monitoring the situation. Later the same month, ECOMOG troops retook the capital and again installed the civilian government, although thousands of rebels were still reportedly hiding out in the surrounding countryside.

In the aftermath of the rebel attack, Special Representative Okelo, in consultation with West African states, initiated a series of diplomatic efforts aimed at opening up dialogue with the rebels. Negotiations between the Government and the rebels began in May 1999 and on 7 July all parties to the conflict signed an agreement in Lome to end hostilities and form a government of national unity. The parties to the conflict also requested an expanded role for UNOMSIL. On 20 August the UN Security Council authorized an increase in the number of military observers to 210.

On 22 October 1999, the Security Council authorized the establishment of UNAMSIL, a new and much larger mission with a maximum of 6,000 military personnel, including 260 military observers, to assist the Government and the parties in carrying out provisions of the Lome peace agreement. At the same time, the Council decided to terminate UNOMSIL.

On 7 February 2000, the Security Council, by its resolution 1289, decided to revise the mandate of UNAMSIL to include a number of additional tasks. It decided to expand the military component to a maximum of 11,100 military personnel, including the 260 military observers already deployed. The Council also authorized increases in the civil affairs, civilian police, administrative and technical components of UNAMSIL, as proposed by the Secretary-General.

The Security Council again increased the authorized strength of UNAMSIL, to 13,000 military personnel, including the 260 military observers by its resolution 1299 of 19 May 2000. On 30 March 2001, a further increase was authorized to 17,500 military personnel, including the 260 military observers. The Council took this decision by its resolution 1346, and, by the same resolution, approved a revised concept of operations.

UNAMSIL: A success story in peacekeeping

UNAMSIL may serve as a model for successful peacekeeping, as well as a prototype for the UN's new emphasis on peacebuilding. Over the course of its mandate, the Mission disarmed tens of thousands of ex-fighters, assisted in holding national elections, helped to rebuild the country's police force, and contributed towards rehabilitating the infrastructure and bringing government services to local communities.

The United Nations also helped the Government stop illicit trading in diamonds and regulate the industry. During the war, rebels had used money from “blood” or “conflict” diamonds to buy weapons which had fuelled the conflict.

UNAMSIL was not always foreseen to succeed: at one point, in May 2000, the mission nearly collapsed when the rebel Revolutionary United Front (RUF) kidnapped hundreds of peacekeepers and renounced the ceasefire in a move that endangered the credibility of UN peacekeeping. Outraged by the chaos that followed, the international community put pressure on the rebels to obey the ceasefire and slapped sanctions against RUF sponsors. Subsequently, UNAMSIL launched new mediation efforts and brought the two adversaries back to the negotiation table. It brought in more troops to monitor the ceasefire and began disarming fighters from both sides.

The United Kingdom , which had sent a force to restore peace following RUF's breach of the ceasefire, later started restructuring the army while UNAMSIL and other international partners concentrated on training the local police force.

By early 2002, UNAMSIL had disarmed and demobilized more than 75,000 ex-fighters, including child soldiers. The Government declared the war officially ended. With the political situation stable, the Mission helped organize Sierra Leone 's first ever free and fair presidential and parliamentary elections by providing logistics and public information support. Two years later, the mission gave similar support for the local government elections.

UNAMSIL completed most of the tasks assigned it by the Security Council: It assisted the voluntary return of more than half a million refugees and internally displaced persons. It helped the Government restore its authority and social services in areas previously controlled by rebels, trained thousands of police personnel, and constructed or reconstructed dozens of police stations.

UNAMSIL monitored and trained Sierra Leoneans in human rights and was instrumental in setting up the Special Court for Sierra Leone to try those most responsible for war crimes. The Mission also assisted the Government in setting up a Truth and Reconciliation Commission, tasked with healing the wounds of war by bringing together perpetrators and victims of atrocities.

Working together with UN agencies, the Mission launched quick-impact and income-generating projects to provide jobs to thousands of unemployed youths and ex-fighters and basic services to local communities. UNAMSIL troops reconstructed schools and clinics, launched and funded agricultural projects, and sponsored free medical clinics in far-flung areas.

While UNAMSIL had done much, Sierra Leone still faced many challenges: the country remained fragile and needed to take concrete steps to address the root causes of the conflict and cultivate a culture of human rights. The economy was heavily dependent on donor funds. A disproportionate share of income from diamond mining still found its way into private hands, rather than Government coffers. Despite reintegration programmes, thousands of ex-combatants and youths—many of whom never went to school—were unemployed. In short, the peace had yet to produce tangible economic dividends and social benefits for the majority of the population.

To help meet these challenges, the Security Council established a new mission—the United Nations Integrated Office for Sierra Leone (UNIOSIL)—to help consolidate peace in the country. Its mandate was to cement UNAMSIL's gains and to help the Government strengthen human rights, realize the Millennium Development Goals, improve transparency and hold free and fair elections in 2007.