Thousands of Palestinian refugees streamed out of the squalid camp overnight, escaping in case the truce between the army and the Fatah al-Islam group collapsed into more fighting.
At least 22 militants, 32 soldiers and 27 civilians have been killed in the fighting this week in Lebanon's worst internal violence since the 1975-1990 civil war. The camp, home to 40,000, has come under heavy army shelling.
A military source said there was calm but added that "the matter is not over".
"It will only end with the final end of this gang", he said.
Rescue workers have been unable to enter the camp near Lebanon's northern port city of Tripoli and it is not clear how many civilians may have been killed there. Residents said bodies were buried under the rubble of buildings.
Fatah al-Islam, a Sunni Muslim militant group, had made Nahr al-Bared their base. Although the faction is led by a Palestinian, the Lebanese authorities say they have arrested Saudi, Algerian, Tunisian and Lebanese members of the group.
The government had pledged to root out Fatah al-Islam, which members of the governing coalition say is a tool of Syrian intelligence. Syria denies any link with the group.
U.N. Secretary-General Ban Ki-moon on Tuesday denounced "criminal attacks" against Lebanese troops fighting Islamist militants in a Palestinian refugee camp and urged immediate access for aid to civilians.
- Reuters - Thomson Reuters Foundation
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