US President Barack Obama on Monday made an appeal to African leaders for their help in bringing peace to South Sudan.

"The possibilities of renewed conflict in a region that has been torn by conflict for so long, and has resulted in so many deaths, is something that requires urgent attention from all of us," said Obama. "We don't have a lot of time to wait."

Ethiopia, the country hosting the leaders' summit, has been among the most active countries in East Africa in trying to end the South Sudan conflict. The warring sides face an August 17 deadline to accept a regional peace and power-sharing deal.

South Sudan was plunged into conflict in December 2013, when forces loyal to former Vice President Riek Machar clashed with those of President Salva Kiir. The conflict descended into a largely ethnic one, with Riek's people being of the Nuer tribe and Kiir's from the Dinka.

US officials have expressed pessimism about the prospects for a deal, saying the leaders of both sides are indifferent to the plight of civilians.

Joining Obama and Ethiopian Prime Minister Hailemariam Desalegn for talks on South Sudan were the presidents of Kenya and Uganda, the chair of the African Union and Sudan's foreign minister.

Praise and criticism for hosts

Obama also used his visit to Ethiopia to praise the country for its efforts in fighting the al-Qaeda affiliated al-Shabab militant group. He said a truck bombing attack on Sunday in the Somalian capital, Mogadishu, which killed 15 people, served as a reminder that "we have more work to do" in stemming regional terrorism.

However, after direct talks with Desalegn, whose ruling party won 100 percent of seats in parliament two months ago, Obama gave the blunt message that Ethiopia needed to improve basic rights.

"There are certain principles we think have to be upheld," Obama added, acknowledging there had been criticism of his visit to a nation with a flawed record. "Nobody questions our need to engage with large countries where we may have differences on these issues," said Obama. "We don't advance or improve these issues by staying away," he said.

Obama is set to become the first-ever US president to address the African Union on Tuesday in the culmination of his short visit to East Africa, which has also involved a visit to his father's native Kenya.

rc/lw (AFP, AP, Reuters)