Nearly six years after conflict broke out in Sudan's western region of Darfur, there is huge frustration in the aid community that the situation remains "blocked", but a unilateral ceasefire recently declared by the government could give peace efforts a much-needed boost if it is honoured, the U.N.'s relief chief said on Friday.

"The key is implementation, not declaration, but I think we should welcome it for what it is and try to make sure it is put into practice because that will then give the actual peace efforts a better chance than they've had in the last couple of years," U.N. Emergency Relief Coordinator John Holmes told AlertNet in an interview before heading off on a 10-day trip to Chad and Sudan.

On Thursday, the U.S. special envoy to Sudan condemned fresh fighting between the Sudanese army and rebels in Darfur, saying the clashes made it difficult to take Khartoum's pledges of peace seriously.

Leaders of the rebel Sudan Liberation Army confirmed attacking a government army base near the settlement of Hilif in North Darfur and said the army had called in an air strike on nearby villages in response. The Sudanese ambassador to the United Nations denied the army's retaliation.

Previous ceasefires and an ineffective May 2006 peace deal have failed to halt the fighting, which flared in 2003 when mostly non-Arab rebels took up arms against the government, accusing it of neglect.

Holmes said the implementation of Khartoum's unilateral truce - declared by the president last week alongside moves to disarm militias and step up development - was vital for improving security for aid workers on the ground. In recent months, access to Darfur's 2.7 million displaced people has deteriorated due to growing violence, with more journeys now being made by helicopter than road, Holmes said.

"The attacks on the humanitarian workers have got worse - and let's be clear that these are attacks by groups linked to rebels, nothing to do with the government - although we also ask the government to provide security in a better way," Holmes said.

The United Nation's latest humanitarian profile for Darfur, released in early October, noted that the crisis "reached a new depth" in the third quarter of this year. It said widespread violence and insecurity continued to uproot people, causing large movements into already overcrowded camps.

In September 2008, access to people affected by the conflict dropped to 65 percent, a level not seen since October 2006. So far this year, 11 national aid workers have been killed and humanitarian premises have been attacked or broken into 144 times, the report said. That compares with 13 deaths and 93 assaults on property during the whole of 2007.

Holmes said there was a need to put pressure on both the government and the rebels to keep up momentum to reach a peace settlement.

"Both sides have got to be ready to negotiate seriously and reach an agreement," he said. "People always point their fingers at the government of Sudan but actually the rebel movements are divided still, without a united platform even for negotiations."

A powerful rebel group, the Justice and Equality Movement (JEM), said on Monday it was ready to discuss Qatar-sponsored peace plans for the Darfur conflict, signalling a possible softening of its stance towards the initiative.

Senior commanders had previously said they would not attend a proposed peace conference in Doha and demanded instead one-to-one talks with Sudan's government.

Holmes has urged donors to keep up funding for aid in Darfur - on which around 4.5 million people depend - amid the global credit crunch and growing humanitarian crises in other countries, including Democratic Republic of Congo and Somalia.

"We're putting a million dollars a year into the humanitarian effort into Darfur, and it's a relatively successful humanitarian effort despite all the difficulties," he said. "But I recognise more than anybody else that there are better uses for that money."

Holmes will also visit southern Sudan, where living conditions remain dire three years after the signing of a peace deal. The aid chief urged the international community not to neglect the region because its peace remained fragile.

"We need to make sure there are some good peace dividends for the south, and...it doesn't slip back into conflict because that would be absolutely catastrophic," he said. "We need to make sure the Comprehensive Peace Agreement (that ended Sudan's 20-year north-south civil war) doesn't unravel, because if it does, there's no chance of peace in Darfur or anywhere else."

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