U.S. Secretary of State Hillary Clinton has warned newly independent South Sudan against falling prey to the “natural resources curse” caused by poorly managed oil wealth.

Speaking at a development conference for South Sudan in Washington on Wednesday, Clinton said the African country must use its vast oil resources to lift itself out of poverty.

The chief U.S. diplomat said too often oil wealth ends up in the hands of the elite, outside interests and corporations, while the people see little or no benefit.

South Sudan President Salva Kiir took part in the two-day conference, which aims to bring together leaders of the world's newest nation and potential investors and donor countries.

South Sudan gained more than 70 percent of Sudan's oil when the two sides split in July.

Secretary Clinton urged Mr. Kiir to live up to his promise to build strong institutions, fight corruption and create a transparent and accountable government.

She also said South Sudan must resolve outstanding issues with Khartoum, including land and oil disputes, and unrest along the oil-rich border region which has displaced hundreds of thousands of people.