Geneva  - The humanitarian air service run by the United Nations could face a shutdown next month in key locations due to a lack of funds, a spokeswoman said Friday.

Emilia Casella from the World Food Programme said the service is used mainly to move humanitarian aid workers into hard-to-access areas, particularly in conflict zones, and also to fly medical supplies to where they are needed.

In many cases, such as in the Democratic Republic of the Congo, the Darfur region of Sudan and Somalia, the flights are considered to be more cost effective and sometimes the only way to get aid to stranded civilians.

"This is the most cost effective way to reach remote parts of Niger, for example, and that replicates itself in numerous countries," Casella said.

In February, the service faced a similar shutdown, but was able to garner some funds to keep most of the operations running for several months. The flights to Niger and Ivory Coast, however, still had to be canceled, as there was not enough money to keep those lines open.

The service to Chad, where many refugees from Darfur are residing in refugee camps, would be cut on August 15 and the flights to Liberia, Sierra Leone and Guinea would be grounded at the end of August, if donors do not provide funding.

"It is absolutely definite that aid workers will not be able to get to parts of Darfur if the service is grounded," Casella said in Geneva.

The total budget for the Humanitarian Air Service for 2009 is 160 million dollars. Less than 40 million have been raised from donors so far, and another 50 million is expected to come in from aid organizations that pay to take the flights.

Non-governmental groups such as CARE International have also expressed concern about the grounding of flights, saying it will hamper their relief operations as well. (dpa)