Riot police run past burning barricades on Saturday during riots in the Kibera slum. Authorities applealed for patience as ballots were counted. ((Karel Prinsloo/Associated Press))

AngryKenyans turned to violence late Saturday after the election commission stopped releasing counts in the country's closest presidential race ever.

Commission chairman Samuel Kivuitu ended the count with opposition leader Raila Odinga about 38,000 votes ahead of President Mwai Kibaki. Only 30 of 210 constituencies remain to be counted.

Earlier Saturday, Kivuitu said he did not know why some areas had still not reported results, two days after the vote was held. He said he had been having trouble getting in touch with returning officers in some constituencies.

Officials said they would not be announcing any more results until Sunday.

"It's unprecedented that it's taking this long [to get final results]," Steve Bloomfield of Britain's Independent newspaper told CBC Newsworld. "In the last elections in 2002, results were known by early afternoon the day after the election."

After waiting since Thursday's vote for results in what observers had said was a race too close to call, angry Kenyans reacted by torching housesandattacking political opponents.

Earlier in the day, tensions erupted into violenceas supporters ofboth candidates predicted victory.

Looting and threats

Supporters of Odinga's Orange Democratic Movement started fires and looted shops Saturday inslums on the outskirts of the capital, Nairobi.

Many of the demonstrators carried machetes and, according to witnesses and journalists, threatened people based on their ethnicity. As riots erupted, police fired tear gas in a bid to quell fighting between Odinga's Luo and Kibaki's Kikuyu tribes.

Police blocked off roads to downtown Nairobi, leaving many streets empty.

In the Kibera slum, Odinga's main constituency, protesters ripped up posters of Kibaki and accused the government of attempting to rig the vote to bring Kibaki back to power.

Kivuitu said he would look into allegations of electoral irregularities made by both sides. However,the head of the European Union observer mission, Alexander Graf Lambsdorff, said there has been no evidence of vote tampering.

Kibaki, 76, was elected in 2002 after the Kenya African National Union ruled for 39 years. He pledged to reduce corruption, and is credited with improving the economy.

Odinga, 62,promised to help the poor.

There are 14 million registered voters in the country, who also voted for 210 members of parliament and local councillors.