ADDIS ABABA, Ethiopia - A vote by African leaders for the head of their bloc's influential executive ended in deadlock on Monday between Gabon's Jean Ping, seeking a new term, and challenger Nkosazana Dlamini-Zuma of South Africa.

Intense campaigns had preceded the vote and dominated the African Union summit in Addis Ababa, where leaders gathered to discuss broadening trade within Africa as well as tackling conflict hot spots.

"We went for an election, and none of the two candidates emerged as a winner," Zambian President Michael Sata said. "The next elections will be held in June."

The deputy AU commission chief, Erastus Mwencha from Kenya, will serve as the executive council's chair until the fresh polls at the next summit.

However, analysts say the vote for the AU agenda-setting position has exposed political fault lines between English- and French-speaking Africa, as well as between different geographic regions.

"The result has shown up divides in the continent," said Jakkie Cilliers, executive director of the Institute for Security Studies in Pretoria. "South Africa worked hard to reduce Ping's support base."

AU sources said the election was tight, with Ping holding a slender lead in three rounds of voting in which neither candidate obtained the required two-thirds majority.

Ping, 69, led Dlamini-Zuma, the ex-wife of South Africa's president and a former foreign affairs minister, in the first three rounds 28 votes to 25, 27 to 26 and 29 to 24, AU sources said.

Dlamini-Zuma was then forced under AU rules to pull out, leaving Ping to face a fourth round on his own, but he still failed to muster the necessary votes in his support.

Ahead of the vote, sources said Ping had been confident of re-election, counting on support from French-speaking West and Central Africa countries.

However, he has appeared to have fallen foul of criticism that he performed poorly in recent crises on the continent, after a year that saw a post-election crisis in Cote d'Ivoire as well as the Arab Spring revolutions.

Dlamini-Zuma, 63, had launched a tough campaign and had the backing of the 15-member Southern African Development Community, and Pretoria lobbied hard across Africa to drum up support.

South African delegates broke into song and dance after the stalemate vote conducted at the two-day summit in the new ultra-modern AU headquarters built by the Chinese and unveiled lastweekend.

Agence france-presse