United Nations Observer Group in Central America (ONUCA)

International Operation Name: United Nations Observer Group in Central America (ONUCA)

International Operation Dates:  1989/11/07 – 1992/01/24

Mandating Organization: United Nations

Region Name:  Central America

Location:  Costa Rica, El Salvador, Guatemala, Honduras and Nicaragua

Canadian Operation Name: Operation SULTAN

Canadian Operation Dates: 1989/12/12 – 1992/01/24

Mission Mandate:

ONUCA was established by Security Council Resolution 644 (1989) of 7 November 1989. The Group's mandate was to conduct on-site verification of compliance by the Governments of Costa Rica, El Salvador, Guatemala, Honduras and Nicaragua with their security undertakings contained in the Esquipulas II Agreement, namely

- the cessation of aid to irregular forces and insurrectionist movements, and

- the non-use of the territory of one State for attacks on other States.

On 27 March 1990, the Council, by its Resolution 650 (1990), authorized, on a contingency basis, an enlargement of the mandate of ONUCA and the addition of armed personnel to its strength in order to enable it to play a part in the voluntary demobilization of the Nicaraguan Resistance.

On 20 April 1990, following the signing by the Nicaraguan parties of a complex series of agreements relating to the voluntary demobilization of the Nicaraguan Resistance in Nicaragua, the Security Council, by its Resolution 653 (1990), decided to expand ONUCA’s mandate to include the additional tasks of monitoring the ceasefire and separation of forces, and the demobilization process.

After the completion of the demobilization process in June/July 1990, ONUCA continued to implement its original tasks and contribute to the peace efforts in the region.

Mission Notes:

Throughout the 1970s, civil wars in El Salvador, Guatemala, Honduras and Nicaragua not only escalated but also became intertwined as guerrilla forces used surrounding countries to launch their attacks and, sometimes, to find safe haven. Such cross-border operations in support of internal, civil wars threatened to disrupt the entire region.


In 1983, the governments of Columbia, Mexico, Panama and Venezuela -the Contadora Group- began to seek ways of reaching a negotiated peace. Their efforts failed, but they nevertheless laid the ground-work for the five Central American nations to seek an agreement amongst themselves to try to reduce tensions. Eventually, on 7 August 1987, Costa Rica, El Salvador, Guatemala, Honduras and Nicaragua signed the Esquipulas II Agreement, named after the city in Guatemala where it was signed. Based on an initial draft by Costa Rican President Oscar Arias Sanchez, the agreement did not declare a cease-fire but instead asked each nation to respect the sovereignty of its neighbours and their right to find their own solutions to their own problems; to encourage the growth of democracy through free elections; and to assist in the return of refugees and displaced persons. In addition, each signatory pledged to neither aid nor offer safe haven to irregular forces using its territory to attack others.

The UN Secretary-General had been kept abreast of the negotiations, and once the agreement spelled out a concrete time-table the United Nations was ready to provide assistance in verifying compliance. The Grupo de Observadores de las Naciones Unidas en Centroamérica (ONUCA – United Nations Observer Group in Central America) was authorized through Security Council Resolution 644 on 7 November 1989. To carry out its mandate, teams of observers would require vehicles for road patrols, helicopters for flights over the more difficult terrain, and patrol boats for operations in the Gulf of Fonseca and other coastal regions.

The Chief Military Observer (CMO) and an advance party arrived in Tegucigalpa, Honduras on 3 December, to set up the ONUCA headquarters. The CMO and his staff quickly visited all five countries to set up regional headquarters and the verification centres from which mobile teams (comprising up to ten UNMOs) would deploy. Smaller operational posts were also created in forward areas where most allegations of non-compliance were made. Because these were border regions with difficult terrain and few good roads, the UNMOs relied upon the local population for their knowledge of roads and tracks, and upon helicopters to conduct observation flights. When they observed incidents of non-compliance, or received complaints, they would inform the offending party or government, request cooperation in undertaking further investigation, and then send their findings to all concerned. They also maintained close contact with guerrilla groups in order to build trust, pass on information, and, most importantly, ensure their own security: in most cases there had been no formal cease-fire between governments and the guerrillas they were fighting (to parallel those between the five states) and as the UNMOs attempted to resolve disputes at the state-to-state level it was essential that they be known to anyone whose paths they crossed.


ONUCA’s mandate was enlarged soon after it was established. On 12 March 1990, following the Nicaraguan elections, the Nicaraguan government and the Government-elect requested UN assistance in the demobilization of Nicaraguan guerrillas. ONUCA would create assembly points, verify their demobilization, and guarantee their security before the guerrillas were given civilian clothes and allowed to return to their homes. On 27 March, the Security Council agreed to this request, approving the Secretary-General’s plan for ONUCA’s involvement.

Almost half of ONUCA’s UNMOs were sent to Nicaragua to support guerrilla demobilization there – as was a Venezuelan infantry battalion. The first guerrillas were demobilized on 16 April, and the process, which involved 19,000 guerrillas in Nicaragua and a further 2,700 in Honduras, was completed by 5 July. ONUCA was then able to return to its original task of verifying compliance, patrolling areas of potential violations, and investigating complaints. Although they did not have the authority to prevent border crossings by armed personnel it was hoped that their presence would deter such activities.

Given the willingness of the five governments to live up to the terms of the Esquipulas Agreement, the presence of the UNMOs was largely a success, and on 5 November it was possible to reduce ONUCA’s strength to 158. Continued progress in stabilizing the situation allowed the Security Council to further reduce ONUCA to 132 while it extended its mandate to 30 April 1992 in the expectation of even greater success.

This timetable was overtaken by events once El Salvador reached an agreement with the guerrillas it had been fighting. Resolution of that civil war promised to bring even more stability to the region and, as a result, on 20 May 1991 Security Council Resolution 693 approved the formation of the United Nations Observer Mission in El Salvador (ONUSAL) to oversee the peace accord there. Subsequently, on 16 January 1992 the Security Council approved the transfer of all remaining ONUCA personnel to ONUSAL. That occurred on 24 January 1991, thereby bring ONUCA formally to an end.

Canadian Operation

Canada began to prepare for ONUCA in October 1989, when warning orders were issued and staff checks made to identify likely candidates for deployment. The UN’s formal request came on 3 December, and once the government had accepted the invitation the tasking order was sent on 12 December under the designation Operation SULTAN. The CAF contingent would comprise thirty-six UN Military Observers (UNMOs) and eight CH-139 Jet Ranger helicopters supported by eighty-four air and ground crew who would form No. 89 Light Observation Helicopter (LOH) Unit (Canadian).

Twenty-three additional personnel would form the National Support Element (Cdn HQ) and communications elements, and three additional officers would serve in ONUCA headquarters. The total size of the Canadian Contingent ONUCA (CCONUCA) would be 146, with the UNMOs posted to ONUCA for a year, and the LOH personnel attached posted for six months.

The first Canadians in theatre were the advance party of nine officers, who arrived on 3 December. A reconnaissance party deployed on 10 December, followed by the communications and Canadian HQ elements and four Jet Rangers and part of the 89 LOH personnel arrived on 23 and 26 February. Most of the thirty-six UNMOs arrived on 9 March 1990. The remaining 89 LOH personnel arrived by the end of the month, but the helicopter unit was to undergo a change. On 6 March, the UN asked Canada to replace four Jet Rangers with four CH-135 Twin Hueys, for their longer range and heavier lift capability. This was approved, the Hueys arriving between 27 and 29 March, and with that the unit name was changed to No. 89 Canadian Rotary Wing Aviation Unit (89 RWAU). Its role was to fly command, liaison, and observer missions during daylight hours only. CAF Hercules from 436 Squadron were also to play a support role throughout the mission, flying to Tegucigalpa, Honduras twice a month until August 1990. Meanwhile, CAF naval personnel conducted operations from patrol craft provided and manned by Argentina. Based in San Lorenzo, Honduras, these boats conducted coastal, ocean, and river patrols.

The UN eventually increased the number of Canadian personnel in ONUCA headquarters to four, filling the positions of Senior Staff Officer (SSO) Air, Deputy SSO Air, Flight Plan Assistant and Senior Operations Officer. With the larger size of the helicopter unit (102 personnel), the Canadian contingent now had a strength of 165 personnel.

Once ONUCA began to draw down, the UN asked Canada to withdraw 89 RWAU and all support personnel, leaving only 30 UNMOs in place The redeployment to Canada occurred between 27 November and 15 December 1990. 89 RWAU ceased all flying operations on 30 November, returning to Canada by CAF Hercules. CAF vehicles and other equipment, which had deployed to ONUCA by commercial transport aircraft, returned to Canada by sea. Seven UNMOs departed when ONUCA downsized again towards the end of the mission. When ONUCA ended on 24 January 1992, the 23 remaining Canadian UNMOs were transferred to the United Nations Observer Mission in El Salvador (ONUSAL). Overall, about 350 personnel served with ONUCA, with two rotations of UNMOs and two rotations of personnel with 89 RWAU. 


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