Hundreds of Palestinian civilians trickled out of a besieged refugee camp Wednesday after a truce in the fighting mostly held overnight. About 15,000, nearly half the camp's residents, fled late Tuesday night when a cease-fire took hold between Lebanese troops and Islamic militants barricaded in the crowded Nahr el-Bared refugee camp, relief officials said. About 1,000 fled Wednesday morning. Those fleeing reported bodies littering the camp's streets and scenes of blasted buildings and destruction. Officials said the bodies of at least 20 civilians have been retrieved from inside. But it was unclear how long the truce would hold, and there were fears that allowing civilians out could be a prelude for a major showdown. The Lebanese government has said it is determined to uproot the militant Fatah Islam, and the army has said its troops were trying to target only militant positions. Fatah Islam, which took up residence in the camp late last year, has vowed to fight a "life or death battle." The cease-fire which went into effect Tuesday afternoon didn't begin to take hold until after sunset. With the guns largely falling silent, thousands of refugees dashed out of the camp after being pinned down since fighting broke out Sunday. Earlier, a convoy of UN relief supplies was hit in renewed fighting as it attempted to enter Nahr el-Bared on Tuesday. The official from the UN Relief and Works Agency said a pickup truck and a water tanker were caught between the lines of the Lebanese army and the militant Fatah Islam fighters and hit as they entered the camp. After a morning barrage, fighting stopped at around 2:30 p.m. after Fatah Islam announced it would stop firing. The halt was "an initiative from us in an attempt to stop the bloodshed of children and elderly. If the Lebanese army abide by it, it will hold," Abu Salim Taha, a spokesman for Fatah Islam, told the Associated Press by mobile phone from inside the camp. The Lebanese military has said it will not be the first to open fire, but refused to commit to a formal cease-fire. Less than an hour later, heavy exchanges of fire and several explosions were heard. The resumption of fighting will also likely prevent six trucks for the UN Relief and Works Agency from entering the camp with relief supplies. It was not immediately known which side resumed firing first. Nearly 50 combatants have been confirmed killed in the fighting, but civilian casualties are not known because relief workers and officials have had limited access into the camp. But relief workers have said they have reports of dozens of houses crushed by bombardment with residents buried inside. The trouble threatened to spread to other refugee camps. Dozens of angry Palestinians burned car tires in the southern camp of Ein el-Hilweh, Lebanon's largest. Protesters also burned tires in Rashidiyeh camp in the south.