The Democratic Republic of Congo's interim president, Joseph Kabila, has taken the lead in early results from last month's landmark elections.
The final result may not be known for several weeks
These results mainly come from the east. Ex-rebel leader Jean-Pierre Bemba is leading in results from the west.
With results from only eight of 62 counting centres known, countrywide tallies may not be available for weeks.
A candidate must secure more than half of the total vote to avoid a run-off presidential election in October.
Despite outbreaks of violence in the build-up to the election, polling day passed without trouble.
But European Union observers have warned that a partial release of results could again stir up tensions.
Provisionally, Mr Kabila has taken almost 90% of the vote in North Kivu, Katanga and Maniema provinces.
In the west, including in the capital, Kinshasa, he is trailing behind Mr Bemba.
But the former rebel leader is by no means dominating the west, because votes are leaking away towards some of the other candidates.
So far western results give Mr Bemba just under 40% of the vote, and Mr Kabila 16%.
The BBC's Arnaud Zajtman in Kinshasa says it is difficult to say whether this trend will continue, but the results do give a clear indication that there is a clear divide between the west and the east, which was badly affected by the civil war.
Thirty-two candidates contested the presidency, while more than 9,000 candidates stood for parliament.
Analysts say it is difficult to predict the parliamentary tally, where several of the other presidential candidates hope that their parties will win a substantial bloc of seats.
EU observers said on Tuesday that there had been disorder at counting centres in the capital.
They called for an investigation into how fires destroyed ballots election offices in Kinshasa.