* U.S. urges Sudan to hold credible election
* Pledges support for 2011 referendum
* U.N. chief says NGOs need "predictable" environment
By Yara Bayoumy
KHARTOUM, May 7 (Reuters) - 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 in Feb. 2010 ahead of the referendum on independence. Both events are at the centre 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 ongoing 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.
NGOS IN SUDAN
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, U.N. humanitarian chief John Holmes, also visiting Sudan, said he welcomed Khartoum’s assurances that new international aid groups would be welcomed into the country.
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 in the country’s west.
Sudan has accused the aid groups of helping build the charges against Bashir.
"This is an opportunity to move on from the problems if we can, to make a fresh start if we can and to create the kind of constructive environment which we need for the future," Holmes said after meeting government officials.
He said that was needed so "agencies working in Darfur or elsewhere can have the confidence to invest, to work safely, to work confidently and to work in a predictable environment".
"We’ve made a good start but we have quite a long way to go. We have quite a lot to mend ... and we need to both work on that very hard for the future," Holmes said.
Before the expulsions, the U.N. and aid groups were running the world’s largest humanitarian operation in Darfur.
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. (Additional reporting by Khalid Abdel Aziz; Editing by Jon Hemming)