Angola's ruling MPLA party is heading for a landslide victory in the country's first parliamentary elections in 16 years, preliminary results show.
With around half of the votes counted, the MPLA had received 81% of the vote, the electoral commission said.
It said the main opposition party, Unita, had polled 10%.
Unita is demanding a re-run in Luanda, saying the voting in the capital was chaotic. An African observer mission said the elections had been credible.
This poll is seen as a vital step in the oil-rich country's recovery from decades of civil war.
Fourteen parties took part in the elections. Full results are not expected for up to 10 days.
Polling was extended after chaos on Friday prevented many people in Luanda province from casting their vote.
Some polling stations opened late and others quickly ran out of ballot papers.
Unita (the Union for the Total Independence of Angola) is now challenging the legality of the poll in the constitutional court.
The party's leader, Isaias Samakuva, said the system in Luanda had collapsed.
Ngola Kabangu, who heads the opposition FNLA party, said the election was extremely flawed.
The MPLA (the Popular Movement for the Liberation of Angola) has branded Unita "bad losers" and is already claiming victory, the BBC's Louise Redvers in Luanda says.
Population shifts in some provinces due to the long-running civil war have added to Unita's woes, with the MPLA winning majorities in traditionally strong opposition areas, our correspondent says.
Observers from the regional grouping, Southern African Development Community (Sadc), said the vote had been "transparent and credible".
"The Sadc mission congratulates the people of Angola on peaceful, free, transparent and credible elections which reflect the will of the people," John Kunene of the observer mission told the AFP news agency.
Luisa Morgantini, head of the EU observer mission in Angola, blamed "woeful organisation" for the problems and said that a failure to provide voter registration lists at polling stations was a violation of the country's electoral laws.
She added that some election officials had failed to show up at some polling stations, and that there was a shortage of the ink used to mark voters' fingers and prevent multiple voting.
In the lead up to the election, Unita accused the MPLA of intimidating its supporters and dominating state media.
Some eight million voters are registered in the country - more than a quarter of whom live in the capital's overcrowded conditions.
The MPLA has ruled Angola since the country gained independence from Portugal in 1975.