President Joseph Kabila remained just short of the majority of votes needed for an outright win in Congo's historic elections as tally verification continued Sunday before an expected announcement of final results.

Amid heightened security and calls for calm after a bitter campaign period, Congo electoral workers labored to certify millions more of an estimated 20 million votes cast in Congo's first balloting in 45 years.

By late afternoon Sunday, only hours before a scheduled announcement stating final results, Kabila had received 49 percent of the votes officially counted and verified, to ex-rebel chief Jean-Pierre Bemba's 16 percent, according to official figures posted on the Internet and compiled by The Associated Press.

CountryWatch: Congo (DRC)

But millions more remained to be officially certified and posted.

Desire Molekela, spokesman for Congo's electoral commission, said Sunday all votes have been counted, but that many ballots are still awaiting official validation. Nearly 14 million votes had been counted, certified and released by Sunday afternoon, out of about 20 million estimated cast by the United Nations.

While results were being posted on an official Web site, Congo electoral officials have been careful not to reveal the exact number of votes tallied, making an independent determination of a winner difficult.

Congo is scheduled to announce overall preliminary results at a news conference late Sunday.

Kabila, the 35-year-old president who helped end Congo's 1996-2002 war as leader of the transitional government, was the presumed front-runner. He has so far drawn his greatest support in the East, where he was born.

Bemba, who led a rebel faction in Congo's wars, is a vice president in the national-unity government and has polled strongly in the overcrowded capital, Kinshasa. Official results from one precinct out of four in the city had yet to be posted Sunday.

Another candidate, Antoine Gizenga, has received at least 10 percent of the vote.

In Kinshasa, trucks full of riot police moved through the streets and a few shots could be heard, but there was no immediate explanation for who fired them.

Bemba and another top candidate among 33 standing in the race, Azarias Ruberwa, have both alleged fraud in the July 30 vote and said they may contest the results. Nineteen lesser candidates have banded together to announce a rerun of the vote.

International observers have identified some irregularities in the run-up to the vote and on balloting day, but many groups say they saw nothing to call into question the results' validity.

Six electoral workers were arrested for vote tampering while working on the vote count in the election, which cost the United Nations almost US$500 million.

U.N. officials have called for calm in recent days and Congo's media regulatory body banned three channels from the airwaves for airing images it ruled were meant to incite Congolese. Some 17,500 U.N. peacekeepers are patrolling in Congo.

If no candidate wins the majority of votes in the first round, a second round will be held, most likely in October. Legal challenges to the vote could push that back. No firm date for the inauguration of a new president has been announced.

The international community is hoping that Congo's 58 million people accept the results of the vote and that a legitimately selected president can lead the massive nation beyond decades of corrupt rule, wars and rampant poverty.

The mineral-rich Central African nation — as large as all Western Europe — has been roiled by war and corrupt rule since winning independence from Belgium in 1960. Congo's last multiparty vote for a leader was in 1961. The winner was killed as military regimes took power.