Mr Savimbi's threat to resume fighting, contained in an address over Unita's 'Voice of the Black Cockerel' radio station, came as returns from legislative and presidential elections last Tuesday and Wednesday continued to show him trailing President Jose Eduardo dos Santos.
Residents of Luanda, who remember the bloody collapse of the transitional government in 1975 at independence from Portugal, reacted quickly to the speech, with restaurants and bars, usually very lively on Saturday night, closing early or not opening at all.
The address shocked United Nations officials and Western diplomats who helped set up the elections and the May 1991 ceasefire which ended the 16-year civil war in this country of 10 million people. Most international observers have declared the vote free and fair and have taken at face value Mr Savimbi's pre-election promises, usually made to Western diplomats, to respect the outcome of the vote. In recent weeks, however, Mr Savimbi had told journalists that only fraud could deprive him of victory and that he would not accept it.
Perhaps the most important reaction came from the United States, which has long backed Unita with official and covert military aid worth several hundred million dollars. After US officials in Luanda were unable to meet with Mr Savimbi, the Assistant Secretary of State for African Affairs, Herman Cohen, sent him a fax on Saturday night urging him to respect the election results and to take any complaints about the vote to Angola's National Electoral Council.
Latest results yesterday showed that with nearly two-thirds of the vote counted, Mr dos Santos's lead was 53 to 37 per cent, as late returns from rural areas continued to bolster Mr Savimbi's count. Some election experts predicted Mr dos Santos would finish with 51 per cent of the vote, barely enough to avoid a run-off election. With nearly 15 per cent of the ballot papers either spoiled or left blank, they argued, Mr Savimbi's National Union for the Total Independence of Angola (Unita) could make a strong argument for a second round of voting.
The controversy sparked by Mr Savimbi's radio address appeared to catch Unita officials off guard, and they spent much of Saturday night and yesterday in damage control.
'It was not a declaration of war, but a warning to the government that the people will not just accept any electoral process,' said Unita's spokesman, Jorge Valentim. He repeated Mr Savimbi's accusations that the ruling Popular Movement for the Liberation of Angola (MPLA) was guilty of stealing ballot boxes and intimidating election officials.
But Mr Valentim would not support Mr Savimbi's charge that the government had manipulated the National Electoral Council, which is overseeing the poll. He said Unita had held lengthy meetings with council officials overnight and that they were investigating a number of complaints.
Leading article, page 18