Updated

Hundreds of demonstrators in Guinea's capital on Monday burned tires and threw rocks at security forces, protesting a close presidential election that has been overshadowed by ethnic tensions.

The demonstrators gathered Monday in a part of Conakry inhabited by members of the Peul ethnic group.

Partial results of the Nov. 7 poll show a tight race, with Peul candidate Cellou Dalein Diallo slightly leading rival Alpha Conde, with half of the electorate counted.

On Sunday Diallo said he would not accept the outcome because two contested counties — Kouroussa and Siguiri — had been included in the total. The two provinces were swept by ethnic riots targeting the Peul in the days before the Nov. 7 ballot. Diallo claims his constituents were too intimidated to vote, and that in many polling stations, his party could not find anyone to represent them and were instead represented by their opponent.

National Independent Electoral Commission President Siaka Sangare said that electoral law does not allow him to annul the provinces without proof of fraud, but he said the commission is investigating the allegations.

This year's vote is considered the country's first democratic election, marking the only time in Guinea's 52 years since independence that the outcome has not been predetermined.

The nation of 10 million on Africa's western coast was a one-party state until the 1990s and has been ruled by military strongmen for the past 26 years. The most recent leader of the military junta was forced into exile after his men carried out a horrific massacre last year, prompting his No. 2 to agree to hand over power to civilians.

International observers say the recent poll was credible overall, even though some irregularities were noted. Experts on Guinea say that the country is unaccustomed to transparency and that both sides are quick to assume foul play, as was frequently the case in past elections.

Riots between Malinke and Peul supporters of the two parties paralyzed the capital in the weeks before the vote and spread as far as 300 miles (480 kilometers) north, where Peul shops were looted in Kouroussa and Siguiri, and hundreds of people fled.