Sudan - The United States is working to push Sudan and South Sudan back from the brink of war as the two sides ratchet up hostilities that threaten to upend the U.S.-backed peace deal that led to South Sudan's independence last year.
The Obama administration's special envoy for Sudan, Princeton Lyman, said on Thursday the situation was a "very serious crisis" that threatened wider conflict between the two foes, which fought a brutal civil war for decades before finally signing a 2005 peace agreement.
But analysts said Washington, which worked hard to ensure that South Sudan seceded peacefully last year under the terms of the 2005 pact, found itself with very limited leverage.
"This is a level of hostility we haven't seen for years," said Jonathan Temin, director of the Sudan program at the U.S. Institute of Peace, a government-funded Washington think tank. "For the U.S., good options are limited right now."
Lyman, speaking by telephone from Khartoum during a trip which also took him to the South's capital, Juba, said the Obama administration was working to nudge both sides back into discussions of their basic security concerns while attempting to cool down the heated rhetoric.
"It's not going to be easy. Emotions are running very, very high," Lyman said. "It is important that we get the parties and our international colleagues together around this fundamental question of security."
Sudan's president, Omar Hassan al-Bashir, vowed on Thursday to teach South Sudan "a final lesson by force" after it occupied a disputed oil field.
The South says the Heglig field, which accounts for about half of the North's remaining oil production, is in its territory. But Khartoum called the seizure an assault on its sovereignty. U.N. Secretary-General Ban Ki-moon on Thursday called the takeover "a clearly illegal act."