African Union leaders wound up a summit here Wednesday with the continent beset by conflict and divided over new chairman Moamer Kadhafi's plans for unifying its 53 member states.

Closing speeches hailed an agreement to change the name of the body's main executive arm but the Libyan leader's election as the organisation's rotating chairman sparked a debate that led to the summit's extension by a day.

"After earnest efforts toward Africa's unity, we were able to agree on transforming the AU Commission into the AU Authority, which is a very significant step," Kadhafi said.

"We Africans have only unity to gain strength. We live in a ruthless world, where the strong live and the weak are enslaved... I want to tell Africa's youth that the power is theirs and that they should push for African unity."

The veteran Libyan leader's vision for a more aggressive integration of the continent into what he calls the "United States of Africa" was met by deep reservations from some key nations.

Wednesday's closing speeches came after late night drama at the AU's Addis Ababa headquarters, when the maverick Libyan leader walked out on discussions over the future of the organisation.

South African President Kgalema Motlanthe said in a joint interview with AFP and his nation's SABC television on Tuesday that proposals for strengthening the AU would be considered only over the next three months.

"The aim is to strengthen and expand a bit on the functions and responsibilities of the Authority," he said.

During the summit, the tensions with Kadhafi were palpable.

Ugandan President Yoweri Museveni proposed turning the AU leadership into a troika, which would mitigate Kadhafi's influence in a role that already has little real power.

"Africans are polite, but deserve respect," Museveni told him, according to one participant in the talks.

Kadhafi has long looked at the AU as a way to boost Africa's international profile, but also to increase his own standing and leaders like Museveni are reluctant to see Kadhafi become the face of Africa in the international arena.

Kadhafi seized power in a coup 40 years ago, and his autocratic rule has drawn fierce criticism from rights groups.

He recently had a group of traditional leaders name him the "king of kings" of Africa, and brought an entourage of seven local monarchs dripping in gold jewellery with him to the summit.

Yet, differences remain over how the new system would be implemented.

Countries such as Libya advocate immediate unification, a position Kadhafi says is the only way forward for the war-ravaged and drought-stricken continent.

On the other hand Nigeria, South Africa, Ethiopia and Kenya seek gradual integration -- and seem to have the upper hand at the moment.

The rift over Africa's unification overshadowed an official agenda focused on infrastructure development.

Many leaders' assessments of the continent's economic future were gloomy during the four-day summit, with Ethiopian Prime Minister Meles Zenawi predicting that "the coming decade or so is likely to be very dark indeed for Africa."

He cited global warming and the world economic downturn, which many AU leaders feared would lead to a slump in trade and cuts in much-needed foreign development aid.

In his closing speech, Kadhafi joined the continent's chorus of praise for US President Barack Obama, the first black man to accede to the White House.

"The black people's struggle has vanquished racism. It was God who created colour. Today Obama, a son of Kenya, a son of Africa, has made it in the United States of America," he said.

"We hope he will be well protected and want him to be undaunted. America doesn't belong to the whites alone. I hope he will be able to accomplish the change he carries in him," Kadhafi added.

The crisis in Zimbabwe and the ongoing unrest in the eastern Democratic Republic of Congo were discussed in separate sessions last week.