Lebanon's prime minister has vowed to wipe out an Islamic militant group barricaded in a Palestinian refugee camp.
Sporadic gunfire yesterday, which grew heavier for a short period after nightfall, marred the two-day-old truce as the army moved troops around the Nahr el-Bared camp.
But Lebanese troops did not attempt to advance, apparently giving time for talks and for the militants to comply with a government ultimatum to surrender or face a military assault.
Fighters from the al-Qaeda-inspired Fatah Islam militant group, estimated in the hundreds, have barricaded themselves in the camp, saying they will fight off any Lebanese attack.
Security officials said army positions came under heavy machine gun fire from Fatah Islam militants followed by rocket-propelled grenades. They said the army "dealt" with the source of fire.
A spokesman for the militants said it was the army that opened fire. He said the group's fighters remain committed to the truce but that they will never surrender or flee.
The fighting broke out Sunday when police raided suspected Fatah Islam hideouts in Tripoli while searching for men wanted in a bank robbery and has killed some 50 combatants and many civilians.
Thousands of Palestinian civilians - mainly women and children - have fled the camp on the outskirts of Lebanon's second largest city, Tripoli, but many thousands remain inside.
UNRWA, the UN agency which cares for Palestinian refugees, said around 15,000 were still in the camp.
"The humanitarian situation in Nahr al-Bared is deteriorating," UNRWA spokeswoman Hoda Elturk said. "We have our trucks full of food and water ready [but] it's not secure enough for our staff to enter."