President Joseph Kabila has told the BBC he will accept the result of the run-off election in the Democratic Republic of Congo "without question".
President Kabila secured 45% support in the first round
He faces ex-rebel leader Jean-Pierre Bemba after winning the first round, but failing to secure 50% of the vote.
Mr Bemba has already told reporters he will not return to war if he loses in a free and fair poll.
It is the last day of campaigning ahead of Sunday's vote. The capital, Kinshasa, is reported to be calm.
The two presidential candidates were belligerents in the civil war and both still have loyal armed forces.
The United Nations has its biggest force anywhere in the world in DR Congo, where it is monitoring a peace agreement between warring factions signed in 2002.
Rival faction violence
Mr Kabila, who took over from his assassinated father in 2002 said his priority if elected was peace and stability in the east - which has remained unstable despite the peace deal which made Mr Bemba one of four vice-presidents.
The 35-year-old president said the country needed to be brought rapidly under control "in order to permit investors to come, in order to allow our people to move from east to west, north to south and live in peace because they're basically peace-loving citizens".
Earlier, UN forces freed one of his key allies from a radio station owned by Mr Bemba using a tank after an armed stand-off.
Nzanga Mobutu, son of late Congolese ruler Mobutu Sese Seko, was campaigning on behalf of President Kabila in Gbadolite, in the north of the country.
Four people were reported killed in rival faction violence in the town.
Mr Mobutu was escorted to Gbadolite airport by UN soldiers after being released and flew off in good health.
A regional spokesperson for the United Nations force told the BBC that Thursday's events were unlikely to have an impact on the presidential run-off.
The stand-off in Gbadolite began on Thursday just hours after rioting broke out at the main prison in the capital, Kinshasa.
A source inside the prison and a human rights groups have told the BBC's Arnaud Zajtman that five inmates were killed in the violence.
Sunday's run-off vote will conclude the country's first fully democratic polls since independence in 1960.