An African Union summit on Monday failed in its efforts to elect the head of the organization's important commission, the union's executive arm and public face.

The contest was between the incumbent, Jean Ping of Gabon, and Nkosazana Dlamini-Zuma, South Africa's former foreign minister and the ex-wife of South African President Jacob Zuma.

Both candidates failed to gather the necessary two-thirds majority. Ping's name was alone on the fourth and final ballot, but 20 abstentions kept him from getting the votes needed to retain his post. Diplomats say the abstentions were a vote of no-confidence in what many see as his failed leadership during this year's crises in Libya and Ivory Coast.

The AU Commission's deputy chief, Kenya's Erastus Mwencha, will serve as chairman until the organization's next summit in Malawi in June. The AU commission deals with matters of trade and security, and makes policy decisions.

This deadlock, which occurred on the summit's final day, is an indication of the split between the African continent's French-speaking nations in the north and a southern bloc led by South Africa and where English is more commonly heard.

The dispute over oil revenue between Sudan and newly independent South Sudan, along with the crisis in war-torn Somalia, were major agenda issues at the two-day summit in Addis Ababa, the Ethiopian capital. It began one day after the dedication of the new AU headquarters funded by a $200 million grant from the Chinese government.