support from West Germany. In 1982, landlocked Zimbabwe directly intervened in the civil war in order to secure its vital transport routes in Mozambique, stop cross-border RENAMO raids, and help its old ally FRELIMO. Zimbabwe's help became crucial to the defence of the corridors, particularly the important Beira corridor. Later Zimbabwe became engaged further, carrying out several joint operations with FRELIMO against RENAMO strongholds. Thus RENAMO had to give up its base camps in the Gorongosa area. Tanzania also sent troops to back FRELIMO. North Korea, the German Democratic Republic and the Soviet Union also armed and trained FRELIMO forces, with the North Koreans establishing a Military Mission in Mozambique during the early 1980s North Korean advisers were instrumental in the formation of FRELIMO's first specialized counter-insurgency brigade, which was deployed from 1983 onward. East Germany provided military assistance and trained members of the Mozambican FPLM in the GDR. In the spring of 1977, the Romanian Socialist Army sent 500 soldiers and officers to Mozambique. The Romanians were deployed to Maputo and Nacala. Specialized in operating tanks, these Romanian troops - under the supervision of some Soviet officers - trained Mozambican tank troops in the use of T-34 and T-54 tanks. Malawi had a complicated relationship with both FRELIMO and RENAMO. During the mid-1980s, FRELIMO repeatedly accused Malawian president Hastings Banda of providing sanctuary for RENAMO insurgents. Mozambican security forces occasionally carried out raids into Malawi to strike at suspected RENAMO base camps in that country, a practice which brought them into direct confrontation with the Malawian Defence Force. In 1986, Malawi bowed to Mozambican pressure and expelled 12,000 RENAMO insurgents. Banda explicitly turned against RENAMO after the disgruntled insurgents began targeting a vital rail line which linked Blantyre to Mozambican ports on the Indian Ocean coast. Beginning in April 1987 the Malawian government deployed troops into Mozambique to defend the rail line, where they were involved in a number of engagements with RENAMO. After 1980, South Africa became RENAMO's main supporter. The FRELIMO government, led by President Machel, was economically devastated by the war and sought to end the conflict and continue the development of Mozambique. Even the military and diplomatic support with the socialist bloc could not alleviate the nation's economic misery and famine as a result of the war. After negotiations, a reluctant Machel signed a non-aggression pact with South Africa, known as the Nkomati Accord. In