South Africa's threat to send its troops into Zimbabwe in pursuit of South African guerrillas marks a major increase in tension between the two countries. South Africa's warning, issued Wednesday, followed a series of five land-mine explosions near the northern town of Messina close to the Zimbabwe border. South Africa has accused Zimbabwe of harboring guerrillas of the African National Congress and allowing them to cross the Limpopo River into South Africa, where the ANC is outlawed.
[The ANC claimed responsibility Friday for the explosions but said that the ANC units that placed the mines were based in South Africa and not in Zimbabwe, Reuters reported.]
Zimbabwe's Cabinet minister for security said Friday that the nation will defend itself against any attack by South Africa.
``The government of Zimbabwe categorically denies any knowledge of the land mine incidents . . . and Zimbabwe reiterates its stance that its territory will not be used as a springboard [for attacks] against any neighboring country,'' Emmerson Munangagwa said. He also said South African anti-apartheid guerrillas have no military bases in Zimbabwe.
In the past, Zimbabwe's prime minister, Robert Mugabe, has firmly opposed an ANC military presence in Zimbabwe. But given the escalation of the South African crisis and his own increased visibility internationally as chairman of the so-called ``nonaligned movement,'' his nation may adopt a more militant stance.
Mr. Mugabe's visit to Moscow this week -- his first since taking office 51/2 years ago -- has taken on added significance in light of the visible deterioration in Zimbabwe's relations with South Africa. Until recently, relations between Zimbabwe and the Soviet Union have been stiffly formal, reflecting the fact that Moscow supported Mugabe's main political rival, Joshua Nkomo, in the liberation war against the whites of Rhodesia (as Zimbabwe was called before 1980).
The prime minister's decision to go to Moscow almost certainly reflects his belief that, as chairman of the nonaligned movement, his visiting the Soviet Union is essential after all his visits to Western countries, including the United States.
Western diplomats here say Moscow may be anxious to offer Zimbabwe military hardware for use in its campaign against the antigovernment guerrillas in Mozambique and to build up its military preparedness in the event South Africa does send troops into Zimbabwe.
The buildup in border tension between Zimbabwe and South Africa comes after a prolonged period in which the two countries apparently improved their working relations, especially in the economic field. Zimbabwe's trade with South Africa has grown faster than that with other African countries. Many of Zimbabwe's tourists come from South Africa. In the last year about 94 percent of all Zimbabwean imports and exports used South African railways and ports.
Zimbabwe's tough line on economic sanctions against South Africa -- repeated here Wednesday by the Zimbabwean foreign minister -- surprised some observers here who had expected Mugabe to adopt a lower profile, given the country's vulnerability to countersanctions by the South Africans.
It appears that there is disagreement within the Mugabe administration as to how far Zimbabwe should go in any economic confrontation. Agriculture Minister Moven Mahachi and Finance Minister Bernard Chidzero are both said to be moderates in the sanctions debate, urging caution on some of their Cabinet colleagues.
Mr. Chidzero warned recently that if economic sanctions were imposed against South Africa, it could mean shortages of some products, increased unemployment, a slowdown in the economy, and ``general hardship.''
Chidzero admitted that transport would be the crucial area, given Zimbabwean dependence on the South African transport system, but went on to suggest that Zimbabwe had some economic muscle of its own.
This is because Zimbabwe's payments to South Africa for pensions, transport services, and investment last year totaled $100 million, compared with only $15 million flowing in the reverse direction. Zimbabwe owes South Africa $120 million for loans incurred before independence, and could, if necessary, expropriate South Africa's substantial investments in Zimbabwe.
For Mugabe, the deterioration in relations with South Africa could pose serious problems, analysts say. As leader of the nonaligned movement, it will not be easy for him to keep denying support for ANC guerrillas.
At the same time, Mugabe is likely to be reluctant to push toward a major military and economic confrontation with South Africa which would have adverse effects not just on Zimbabwe but also in the region as a whole.