A convoy of U.N. relief supplies was hit in renewed fighting as it attempted to enter the Palestinian refugee camp of Nahr el-Bared, and there are possible casualties.
The official from the U.N. Relief and Works Agency said a pickup truck and a water tanker were caught between the lines of the militant Fatah Islam fighters and the Lebanese army, which fired at the convoy.
"The army hit the place where the pickup truck and the tanker were. The army knew we were there and emptying our goods," the U.N. relief official told The Associated Press by telephone from the entrance of the camp.
"There may have been some casualties, at least one," the official said, speaking on condition of anonymity because he was not authorized to talk to the media.
"Maybe there was no coordination between the two sides ... maybe it was an accident," he added.
The Lebanon representative of the Palestinian militant group Islamic Jihad, which has been mediating a cease-fire, confirmed relief efforts had come under attack.
Speaking on al-Jazeera television, Abu Imad Rifai said that while people were "trying to pick up food supplies for UNRWA they were shelled and some were injured, some seriously."
Rifai said he did not know who had breached the cease-fire, but questioned whether a third party could be contributing to the fighting.
"Are there other parties getting involved and shooting and shelling occasionally?" he said.