Two Lebanese soldiers were killed during clashes with Islamic militants at the Nahr el-Bared camp, the army said.

Columns of tanks rolled nearby as Lebanese troops entered the northern edges of the refugee camp, breaking more than a week of relative calm in the fighting between the army and Fatah al-Islam.

Troops also pounded the camp with 155 mm shells in what is the heaviest daytime artillery fire seen since the beginning of the campaign. Lebanese security sources said the militants were pinned down in one area.

The violence began on May 20 when Lebanese internal security forces were conducting raids in a Tripoli neighborhood following a bank robbery. The raids triggered clashes near the refugee camp after, army sources say, Fatah al-Islam militants shot at the troops, who returned fire.

The battles are the worst internal violence since the end of Lebanon's civil war in 1990.