"As a result of this incident, drivers and truck owners are losing confidence in UN assurances," Amer Daoudi, a WFP relief co-ordinator, told Aljazeera.net on Wednesday.
"The incident will definitely affect our operations and will make it extremely difficult to bring in more aid to southern Lebanon," he said about the death of the UN observers in the southern hilltop town of Khiam.
However, he said UN relief agencies would continue to send supply trucks and will coordinate with all warring parties to ensure safe passage for their convoys.
Earlier in the day, WFP dispatched the first UN aid convoy from Beirut to the southern port city of Tyre, one of the hardest hit areas now home to thousands of displaced people.
While the distance between Tyre and Beirut is only 83km, the widespread destruction of roads and bridges, as well as the targeting of commercial trucks, has made the relief operation highly dangerous, officials are saying.
Continued Israeli bombardment of southern villages and towns have also made it difficult for relief and aid agencies to accurately assess the conditions and needs of people trapped there.
"While thousands have fled Tyre, tens of thousands still remain stranded with no fuel for their cars, no money for skyrocketing taxi fares and dwindling supplies of food. They have no assurances that they can safely leave. We have to assist these people before their situation deteriorates even further," Daoudi said.
"Tens of thousands still remain stranded with no fuel for their cars, no money for skyrocketing taxi fares and dwindling supplies of food"
WFP relief co-ordinator
The 10-truck convoy that WFP managed to send to the south carried 90 metric tonnes of wheat flour donated by the Lebanese government and supplies from UN Children's Fund (Unicef), the World Health Organisation (WHO) and the UN Relief and Works Agency for Palestine refugees (UNRWA).
The aid is given to local authorities, such as municipalities, as they know more information about the new locations of their fellow villagers, their conditions and their needs.
Medecins Sans Frontieres (MSF) or Doctors Without Borders also transported over 50 tonnes of supplies from Cyprus to Beirut by sea and from Syria over land to Beirut.
The MSF head of mission in Lebanon, Annik Hamel, says her team have been able to evaluate the needs of 100,000 displaced persons in the Mount Lebanon region of Chouf.
She said that new families continue to arrive every day and the villages are already saturated. The villagers shelter the displaced either in their homes or in public facilities such as schools and public halls, and offer them food, water, and mattresses.
There are also doctors and nurses – all Lebanese volunteers – that come to carry out consultations and provide medical care.
"The situation is deteriorating. Among the displaced there are people who are sad, depressed. They say that their village is still being bombarded, that family members are still lying under the rubble, that they could not bury their dead. They have lost part of their family," Hamel told Aljazeera.net.
"Food and water could become scarce as more families flee the south of the country. Certain medicines - particularly for chronic pathologies - are also running low"
Annik Hamel, the MSF head of mission in Lebanon
She warned that food and water could become scarce as more families flee the south of the country. Certain medicines – particularly for chronic pathologies – are also running low.
MSF says they are expected to bring in an additional 35 tonnes of aid including 2,000 family tents, 20,000 blankets, 2,000 hygiene kits, 2,000 cooking kits and medical kits.