The African National Congress won its fifth straight national election in South Africa, while its main rivals whittled away at its majority.

With 15.6 million ballots from 91 percent of the 22,263 polling stations counted, the ANC had won 62.8 percent of the vote, followed by the Democratic Alliance with 21.9 percent, provisional figures from the Independent Electoral Commission showed. The ANC won 65.9 percent and the DA 16.7 percent five years ago.

"I don't think the results will change significantly at the close," Mark Rosenberg, an Africa analyst at Eurasia Group, a New York-based risk advisory company, said in phone interview Wednesday. "The DA is a relative winner as it benefited from higher turnout in urban areas, signaling that it made important inroads among urban blacks."

The ANC's margin of victory may reduce pressure to make further concessions to its labor and communist party allies, and to stem a loss of support to the newly formed Economic Freedom Fighters, which called for the state to play a bigger role in Africa's second-largest economy.

The EFF, started in October by former ANC youth wing leader Julius Malema, was third with 5.6 percent. The party won backing from miners in the nation's platinum belt, who have been on strike for more than three months for higher wages, and unemployed urban youths who back its proposals to nationalize mines, banks, and land.

Twenty years after taking power under Nelson Mandela, the ANC still enjoys strong backing among the black majority for ridding the country of white-minority rule. The party consolidated its support by providing welfare grants to almost one in three citizens and increasing access to housing, water, and electricity.