Aid groups are concerned about the humanitarian situation in Nahr al-Bared where the fighting is obstructing supplies to about 3,000 refugees still in the camp.
The International Committee of the Red Cross said that the refugees face a new threat from unexploded munitions which were also obstructing relief aid.
"The Palestinian refugees are not being treated properly by Lebanon"
Sunny, Ottawa, Canada
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Jordi Raich Curco, the ICRC's chief in Lebanon, said: "It is becoming extremely difficult to mount relief operations, not only because of the deteriorating security conditions, but also because debris and rubble and unexploded ordnance on the camp's roads are obstructing the way for ambulances and relief vehicles."
In all, 108 people have been killed in the unrest that has exacerbated sectarian and political tensions in Lebanon.
It is the deadliest internal fighting since the end of the 1975-1990 civil war, although there have been much higher death tolls since in a series of Israeli offensives against Lebanon.
On Wednesday, a military prosecutor indicted 11 men from Fatah al-Islam for "acts of terrorism" - a charge that risks the death penalty - bringing to 31 the total charged since the gun battles first started.
The men have been able to resist the army's superior fire power during the 19-day standoff, although the mainstream Palestinian Fatah movement reported that the resolve of the fighters was weakening and some were surrendering.
Lebanese security has also been shaken by a series of bomb blasts in and around Beirut and on Wednesday police said a bomb was defused in the southern port city of Tyre, a stronghold of Shia armed groups.
In Amman, a Jordanian prosecutor called for Shaker Abssi, the Fatah al-Islam chief, to face the death penalty in a case involving the infiltration of armed fighters into Iraq.
Palestinian born Abssi, who turned up in Lebanon after serving a jail term in Syria, was also sentenced to death in absentia in 2004 for his alleged involvement in the murder of an American diplomat in Amman in 2002.
Also on Thursday, Lebanese security forces found three car bombs in the east of the country, Reuters reported.
The bombs were found in the village of Bar Elias, west of the country's border with Syria.
The discovery comes a day after security agents arrested three suspected al-Qaeda members in possession of weapons and explosives in the same village.
The nationalities of the three arrested individuals could not immediately be confirmed.