NAHR AL-BARED, Lebanon (Reuters) – Three Lebanese soldiers were killed in pitched battles with al Qaeda-inspired militants at a Palestinian refugee camp on Sunday as Lebanon’s worst fighting since the civil war entered its 10th week.

Security sources said 15 more soldiers were wounded in the fighting with Fatah al-Islam militants at Nahr al-Bared camp. There was no immediate word on militant casualties.

The deaths brought to 116 the number of soldiers killed in the battles that began on May 20. More than 81 militants and at least 41 civilians have also died.

The army has pushed slowly into the camp, fighting close-quarter battles with Fatah al-Islam militants after bombarding its positions with artillery and tank fire to try to force the group to surrender.

Witnesses said the army concentrated its latest artillery shelling on pockets still held by Fatah al-Islam near the camp’s main road and the northeastern area.

The camp, home to 40,000 refugees before the hostilities, has been completely destroyed and its rebuilding is expected to cost hundreds of millions of dollars. Its residents have sought shelter in other Palestinian refugee camps.

The Nahr al-Bared violence is undermining stability in Lebanon, already paralyzed by a political crisis and shaken by fatal bombings whose victims include two anti-Syrian politicians and six U.N. peacekeeping troops in the past eight months.