KHARTOUM - U.S. special envoy Scott Gration called on Sudan on Thursday to carry out credible elections, due next year, and pledged Washington's support for a referendum on southern independence set for 2011.

Sudan is due to hold its first democratic presidential and parliamentary elections in two decades next February ahead of the referendum on independence. Both events are at the center a 2005 peace deal ending a north-south civil war.

We want to see elections that are carried out, elections that are credible, Gration, on his second visit to Sudan in as many months, said after meeting prominent northern and southern government officials.

It is our decision that we will support the referendum, that we'll support the CPA (2005 peace deal), and we'll push very hard that it's fully implemented, Gration said.

Gration's visit is a sign the diplomatic detente between Washington and Khartoum may be thawing, despite the separate conflict in the western region of Darfur which U.S. President Barack Obama has called a genocide.

Sudan's government rejects this charge.

Gration, named Washington's envoy to Sudan in May, also called for the passage of legislation that are seen as pre-requisites for a free and fair election and referendum.

The former rebel Sudan People's Liberation Movement (SPLM), which fought northern Sudan in a two-decade civil war but now runs the southern government, has accused the north of trying to block such laws on media, national security and other issues.

We also believe that we have to start right now to pass the laws that are required so that we can get a referendum so that the will of people is demonstrated in a way that's credible and in a way that can be accepted by all sides of the international community, Gration said.

EXPAND OPERATIONS

Northern and southern armies have clashed on occasion since the 2005 peace deal, most recently last year in the central oil region town of Abyei, claimed by both north and south.

Separately, Sudanese Humanitarian Assistance Minister Haroun Lual Ruun said Sudan would allow U.N. agencies and NGOs still present in the country to expand their operations, a move which aims to narrow the gap left by aid groups expelled in March.

U.N. humanitarian chief John Holmes, who is in Khartoum, welcomed the move. He next travels to the south and Darfur.

If we can establish the right kind of rebuilding of confidence and trust between the humanitarian community and the government and the authorities, if we have the right kind of operating environment, then we can actually rebuild and replace the capacity that was lost in an effective way, he said.

Sudanese President Omar Hassan al-Bashir expelled 13 international NGOs in March after the International Criminal Court issued a warrant for his arrest on charges of masterminding war crimes in Darfur.

Sudan has accused the aid groups of helping build the charges against Bashir.

Before the expulsions, the U.N. and aid groups were running the world's largest humanitarian operation in Darfur where about 4.7 million people rely on humanitarian aid.

U.N. officials say as many as 300,000 people have died and more than 2.7 million driven from their homes in almost six years of ethnic and politically motivated violence in Darfur. Khartoum says 10,000 have died.

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