APW19980430.0870 NEWS NEWSWIRE South African President Nelson Mandela said Thursday that his two-day state visit here was ``very successful'' in achieving its twin goals of deepening political ties and paving the way for increased trade between the two countries. Mandela said at a joint news conference with President Jose Eduardo dos Santos that South Africa was keen to invest in Angola's oil sector and in the rebuilding of regional transport infrastructure. Much of Angola's infrastructure was devastated by the country's two-decade civil war which ended in 1994 with a peace deal between the government and the rebel movement UNITA. UNITA _ the Portuguese letters stand for National Union for the Total Independence of Angola _ seized control of about half the country during fighting in which a half million people are believed to have been killed. A peace accord signed in 1994 in the Zambian capital Lusaka provided for an end to the conflict. Dos Santos said the two leaders had ``overlapping points of view in all (political) matters.'' Mandela was accompanied on his first state visit to Angola by six government ministers and 45 businessmen who held separate talks with their local counterparts. Dos Santos said he was certain that implementation of the peace pact, which is running more than a year behind schedule due to lingering mistrust between the former foes, would stay on track. ``There are no conditions for either side to return to full-scale war,'' Dos Santos said. However, he appealed to the international community to keep up the pressure on UNITA leader Jonas Savimbi to relinquish control over the few rural areas the rebels still hold. The U.N. Security Council agreed unanimously Wednesday to keep U.N. military observers in Angola until June 30 and endorsed U.N. chief Kofi Annan's plan to withdraw all but a handful of U.N. troops by that date. In private talks, Mandela sought to soothe Angolan concerns over South African foreign policy following his announced retirement after next year's election. Mandela, 79, told Dos Santos there would be no change in direction after his heir apparent, Deputy President Thabo Mbeki, takes over, according to Angolan officials who spoke on condition of anonymity. The officials described Mbeki's relations with Dos Santos as ``cool.'' Mbeki did not accompany Mandela on the visit. Dos Santos also pledged to continue withdrawing Angola troops from the Republic of Congo where they last year helped Gen. Denis Sassou-Nguesso overthrow elected President Pascal Lissouba. Angola's support for the power grab, coming soon after its military help for Congo's Laurent Kabila who ousted longtime Zairian dictator Mobutu Sese Seko in May, had reportedly angered Mandela and strained relations with Dos Santos. (cs/bh/krt)