Sporadic gunfire and artillery shelling rang out from a Palestinian refugee camp in northern Lebanon on Sunday as the army fought to uproot Fatah Islam militants holed up in the settlement. The intermittent fighting came a day after some of the heaviest fighting since June 1, when the Lebanese army - using tanks and artillery - launched a fresh offensive to drive out the Fatah Islam militants. Security officials said five soldiers were killed during the intense fighting Saturday and 15 wounded, some seriously. The officials spoke on condition of anonymity because they were not allowed to give official statements. Another soldier, wounded earlier at the camp, died of his wounds Saturday, bringing to 52 the number of soldiers killed in the fighting that began May 20 - the worst internal violence in Lebanon since the 1975-90 civil war. In a statement issued Saturday, the army said it had taken control of several buildings, clearing them of mines and explosives. "The troops are continuing to tighten the grip on the gunmen in order to force them to abandon their weapons and surrender," the army statement said, adding that some of the militants were fleeing to residential areas inside the camp. A senior Fatah Islam commander denied reports that the army was making advances and said fighters were holding their ground against the soldiers. "We are on the front lines across from them," Abu Hureira, Fatah Islam's deputy commander, told The Associated Press by telephone from inside the camp Saturday. Abu Hureira, a Lebanese whose real name is Shehab al-Qaddour, dismissed as rumors some media reports that he or Fatah Islam leader Shaker Youssef al-Absi had been wounded. He said some fighters were lightly injured "but it's nothing compared to them," he said, referring to Lebanese army casualties. He said the militants were still fighting with the same tenacity, claiming that Fatah Islam fighters attacked an army position on the northern edge of the camp Friday and seized weapons from Lebanese army soldiers. Recent civilian casualties inside the camp are not known because the camp has been closed to journalists and aid workers for days. Although most of Nahr el-Bared's residents have fled, thousands of civilians remain inside.