|PIC1| The U.N.'s World Food Programme on Tuesday said it was cutting back its humanitarian air services in Sudan due to a $48 million (25 million pounds) funding shortfall.

Aid agencies said the reductions would seriously undermine their work in some of the most remote and hostile corners of the country, particularly Darfur and south Sudan.

The World Food Programme (WFP) said it was cutting one of its six helicopters and two of its 18 airplanes - all used to ferry aid workers and supplies around Africa's largest country.

The agency said it would also more than double the charges for helicopter flights, reduce the number of flights from Khartoum and consider cutting the service further in July to cope with the funding gap.

"The measures announced today are aimed to keep vital services going for longer, while we wait for new funding to be confirmed," said Kenro Oshidari, the WFP's representative in Sudan. "Undoubtedly, this is a blow to the humanitarian effort in Sudan."

Aid groups said the move would hit their ability to reach some areas of Sudan where communities are struggling to cope with decades of conflict, poor harvests and underfunded health services.

"Any cuts like this have a huge impact on our work," said Alun McDonald, spokesman for the charity Oxfam in Sudan.

"Just in Darfur, we use this service every day. The big worry is that this could be the first step and we could see further cuts That would be disastrous."

McDonald said Oxfam had to rely on the U.N. air service to reach some parts of Darfur because a surge of bandit attacks had made it too dangerous to travel by road. The looming rainy season would make travelling by land even harder, he added.

The WFP halved its deliveries of emergency food aid to Darfur from May because so many of its convoys were being attacked by armed groups.

The U.N. agency said on Tuesday it had already cut one of its helicopters and would stop using the two aircraft from June 19. The price of its helicopter flights would rise to $100 from $40 from July 1, it added.

WFP spokeswoman Emilia Casella said the WFP might be able to replace its helicopter and give the two airplanes a reprieve if it received $20 million by Sunday. But, although the agency did have some pledges in the pipeline, they still fell short of that amount, she added.

The air service, which last year also carried out 267 security and medical evacuations in Sudan, still needed to raise $48 million out of its budget for 2008 of $77 million, she said.

The WFP had warned it might have to close its Sudanese air service down altogether earlier this year, but received donations from a string of donors including Not On Our Watch, a charity co-founded by Hollywood actors George Clooney, Brad Pitt, Matt Damon and Don Cheadle.