Angola's leading opposition party said on Thursday it filed a legal complaint challenging last week's election results, which saw the long-ruling MPLA win by a significantly reduced majority.
"The complaint about the final results was filed with the (national electoral commission) today," Faustino Mumbika, national secretary of the National Union for the Total Independence of Angola (UNITA), told AFP via WhatsApp message.
The August 24 elections were the most hotly contested in the oil-rich country since its first multi-party vote in 1992.
Results declared on Monday placed the Movement for the Liberation of Angola (MPLA) as the winner with 51.17 percent of the vote, securing a second term for President Joao Lourenco, 68.
UNITA made significant gains, earning 43.95 percent of the vote, up from 26.67 percent in the previous election in 2017.
But earlier this week the former rebel movement led by Adalberto Costa Junior, 60, said it did not "recognise the results" from the national electoral commission.
The MPLA has traditionally wielded control over the electoral process and opposition and civic groups had raised fears of voter tampering.
Four of the 16 electoral commissioners did not sign off on the final results, expressing doubts about the process.
UNITA is contesting the vote's outcome, alleging discrepancies in the count, but similar attempts have failed in the past.
The complaint with the electoral commission is the first step in a process that can take more than a week.
Earlier on Thursday, Artur Torres, a spokesman for the country's Constitutional Court explained that after the commission reaches a decision, the complainant can appeal before the court.
Last week, Costa Junior called for an international panel to review the count.
The MPLA has been the only party to govern the country since it gained independence from Portugal in 1975, but saw its poorest showing in this year's ballot, down from its victory with 61 percent in 2017.
Turnout was low, with only about 45 percent of those registered bothering to cast their ballots.