Clinton urges Sudan, South Sudan reconciliation - USA TODAY

Clinton flew to South Sudan's capital of Juba for a brief visit to congratulate the nascent nation on its anniversary and offer U.S. support, but, more importantly, to stress the urgency of ending disputes with Sudan over oil and territory. Those disputes have led to clashes between the two countries which many fear could crater the 2005 peace deal that ended what was then Africa's longest-running civil war.

"While South Sudan and Sudan have become separate states, their fortunes and their futures remain inextricably linked," Clinton said at a news conference. "Now it is urgent that both sides, north and south, follow through and reach timely agreements on all outstanding issues. The people of South Sudan expect it."

The two sides had faced a Thursday U.N. Security Council deadline to reach agreement on the issues or face possible sanctions, but the council deferred action until at least Wednesday.

Before Clinton's visit, a senior U.S. official, speaking on condition of anonymity because he wasn't authorized to discuss the matter publicly, said Clinton would express concern about a "lack of movement" in resolving the situation but also reaffirm America's strong support for South Sudan, the world's newest nation. The U.S. was instrumental in helping to negotiate the 2005 peace agreement, and the official said Washington is "heavily invested" in its success.

The disputes, particularly over oil revenue, have led to severe economic problems in both Sudan and South Sudan. But the South, which celebrated its first year as an independent nation last month, is in a more precarious situation as it is more heavily dependent on outside assistance.

Clinton urged the two sides to reach an interim agreement on oil revenue sharing so revenue would start flowing again.

"A percentage of something is better than a percentage of nothing," she said at a news conference with Nhial Deng Nhial, South Sudan's foreign minister.

Nhial said his government wants the U.S. to continue its support and to exert pressure on Sudan to accept the proposals South Sudan has made.

Clinton spoke after a meeting with South Sudan President Salva Kiir.

The mostly black African tribes of South Sudan and the mainly Arab north battled two civil wars over more than five decades, and some 2 million died in the latest war, from 1983-2005. It ended with the 2005 peace pact that led to last year's independence declaration for South Sudan.

Though the breakup was peaceful, hostilities flared earlier this year.

South Sudan inherited about three-quarters of the region's oil, but shut down its oil industry in January after accusing Sudan of stealing oil that the South must pump through Sudan's pipelines. That decision has cost both governments dearly in lost revenue.

In April, the two countries' militaries fought over the disputed, oil-rich region of Heglig. South Sudan troops took over the town from Sudanese forces, but that offensive maneuver was condemned by world leaders. South Sudan says it then retreated from Heglig, though Sudan says its forces pushed the South out.