US President George W. Bush has invited his Sudanese counterpart Omar al-Beshir to sign an expected peace accord with the country's southern rebels in Washington, the state news agency SUNA said Monday.

Bush telephoned Beshir and proposed that "the signing ceremony for a peace accord between the Sudanese government and the Sudan People's Liberation Army (SPLA) take place in Washington," it said.

The White House, meanwhile, said Bush on Monday telephoned both Beshir and SPLA leader John Garang asking them to resolve final differences ahead of a peace accord.

"Both calls were upbeat and positive," said spokesman Scott McClellan, adding that Bush "congratulated each leader on the progress made thus far" in the peace process.

"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," the White House spokesman said.

Sudanese Foreign Minister Mustafa Ismail said last week that an agreement would be "signed at the end of the current year".

Vice President Ali Osman Taha and Garang on Sunday began talks in Kenya aimed at finalising an accord.

Since 1983, a civil war has pitted the SPLA, representing mainly animists and Christians in southern Sudan, against successive Arab and Muslim governments in Khartoum.

Meanwhile, Bush on Monday alos signed a decree authorizing US authorities to resume financial aid to Liberia.

With the move, Bush waived mechanisms imposed to prevent Liberia receiving US funds after it defaulted on its debt, determining that "the furnishing of assistance to Liberia is in the national interest of the United States".

The waivers related to section 620 (q) of the Foreign Assistance Act and section 512 of Fiscal Year 2002 and 2003's Foreign Operations, Export Financing, and Related Programs Appropriations Acts, applied to countries in default for more than six months on loans made by the United States.

Liberia's former president Charles Taylor left office in August pressured by the international community, especially the United States.

Since October 14, businessman Gyude Bryant has headed the transition government as interim president charged with taking Liberia into 2005 general elections.

The presidential decree was addressed to the Secretary of State, the Treasury Secretary, the Defense Secretary and the administrator of USAID - Sapa-AFP.