Security officials said at least five Katyusha rockets landed in farm fields in the northern Akkar region, a few miles north of the Nahr el-Bared camp, where Al Qaeda-inspired Fatah Islam militants have been fighting the Lebanese army.
No casualties were immediately reported, said the officials, speaking on customary condition of anonymity because they were not authorized to give press statements.
Meanwhile, heavy fighting continued at Nahr el-Bared as the army pounded suspected militant hideouts with artillery shells and tank fire.
The fighters responded with machinegun fire and rocket-propelled grenades, according to the officials.
The army was making progress toward Fatah Islam positions, the officials said. Witnesses also reported seeing a few Lebanese flags hoisted on the roofs of destroyed buildings inside the camp where the army appeared to be in control.
The state-run National News Agency said the army was encircling a group of Fatah Islam fighters hiding in one of their shelters inside the camp. It said the army had killed a number of fighters whose bodies were lying in the camp streets. The reports could not be immediately verified.
The use of Katyusha rockets appears to be a new tactic by the militants to ease the military pressure and expand the battles outside the camp. The militants fired at least six Katyusha rockets Saturday and 19 rockets on Friday that crashed into villages neighboring the camp, slightly injuring two people and causing damage to property.
One Lebanese soldier was killed in Saturday's clashes and another died of fatal wounds he received Friday, raising to 96 the number of soldiers killed since fighting between the army and Fatah Islam militants erupted May 20 in the Nahr el-Bared, located on the outskirts of the northern port city of Tripoli.
A senior Palestinian official told reporters in the nearby Beddawi refugee camp Saturday that "not more than 70" Fatah Islam fighters remained in Nahr el-Bared. Sultan Abuleinein, head of Palestinian President Mahmoud Abbas' Fatah faction in Lebanon, has called for the Islamic fighters to be eliminated since the fighting began.
At least 60 militants and more than 20 civilians have been reported killed in the fighting, the country's worst internal violence since the 1975-90 civil war.