The United States is "gravely concerned" about the humanitarian crisis in Sudan and South Sudan and is sending up to $26 million to help refugees displaced by the African border conflict, an administration spokesman said Tuesday.

President Barack Obama authorized the emergency relief for refugees from the conflict in two Sudanese border states. The money will go to the United Nations humanitarian agency effort to provide food and protection to some 140,000 Sudanese refugees who have fled bombing and desperate conditions along the border.

A day earlier, Obama had asked South Sudan President Salva Kiir in a telephone conversation to ensure that South Sudan's military exercises maximum restraint and is not involved in or supporting fighting along the border, the White House said. Obama urged a quick agreement on the flow of oil, the issue that has brought the newly separate countries close to war.

The refugees have mostly fled into neighboring South Sudan and Ethiopia. Sudan has refused to allow aid agencies into the region.

The refugee plight was the subject of a meeting between Obama and actor-activist George Clooney at the White House last month.

The U.S. Agency for International Development estimated last month that 250,000 people are on the brink of a famine.

Clooney urged Obama and other leaders to act quickly to bring in new humanitarian aid before the onset of a rainy season that will make it impossible for aid workers to reach some refugees.

"The United States is gravely concerned by the situation in South Kordofan and Blue Nile" in Sudan along the South Sudan border, White House National Security Council spokesman Tommy Vietor said Tuesday. "We continue to call upon the government of Sudan to allow full and unfettered access for international humanitarian agencies."


Sudan is bombing oil-rich regions of South Sudan in order to scare away American and Chinese investors, a South Sudan official said Monday. The Sudan government in Khartoum said that was "false and unfounded."

Oil-producing South Sudan split from the rest of the largely Arab country last year. Landlocked South Sudan shut down oil production in January, saying that its northern neighbor had stolen oil. Thu shutdown has deprived both countries of a critical revenue stream.