Washington, DC — In a surprise move to propel Sudan towards a peace settlement, U.S. President George W. Bush on Monday telephoned Sudan president Omar al-Beshir and SPLM/A rebel leader, John Garang.

The conversation lasted half an hour with each man, according to an administration official speaking on background who, when asked if Bush had promised the two men anything, said: "When a president makes a call like this, of course something is offered."

"Both calls were upbeat and positive," White House spokesman Scott McClellan said. "The President congratulated each leader on the progress made thus far in the Sudan peace process, and indicated that he was watching the peace process closely."

"The President encouraged each side to demonstrate the flexibility to resolve their remaining differences and take the final steps to complete a just and comprehensive peace agreement," he said.

Bush also told the two men that peace in Sudan would make the nation a "beacon of reconciliation," McClellan added.

A White House source confirmed that both Bashir and Garang were told that they would be invited to Washington and the White House upon signing a peace deal.

The administration is anxious to claim success in facilitating an end to Sudan's long conflict and has invested more diplomatic capital in a Sudan settlement than in conflicts anywhere else in Africa.

Secretary of State Colin Powell visited Sudan in October and said while there that he envisioned a peace settlement by the end of this year. Negotiations have however been slowed by continuing differences over contested areas in Western Sudan.

President Bush is believed to be willing to announce that Sudan can be taken off the 'terrorist list' if a settlement is reached. The administration is also reportedly ready to commit millions in new reconstruction funds following a settlement.