Lebanese army troops unleashed barrages of artillery and tank shells Wednesday at Islamic militants in a Palestinian refugee camp in northern Lebanon, witnesses and security officials said.

In some of the heaviest bombardment of Nahr el-Bared in weeks, army cannons fired shells at a rate of 8 to 10 every minute at suspected Fatah Islam positions inside the camp. The shelling could be heard in the nearby port city of Tripoli for several hours before it subsided around mid-morning, witnesses said.

The army action, which began at dawn Wednesday, follows days of low intensity fighting during which soldiers continued to push their way deeper into the camp, seizing weapons and other military equipment from tunnels dug by the militants.

A senior military official said Wednesday that two soldiers were killed in military operations a day earlier, raising to 118 the number of troops killed since fighting with the Al Qaeda-inspired militants broke out in the camp on May 20.

Security officials, who also asked to remain anonymous because they were not authorized to talk to reporters, said the army shelling on Wednesday had mainly targeted the Saasaa neighborhood of the camp, where remaining militants are thought to be hiding in underground shelters and bunkers.

The state-run National News Agency said the shelling destroyed a number of buildings and that troops stormed a shelter, killing several fighters hiding inside. The report could not be independently confirmed.

It said two Katyusha rockets were fired from inside the camp, landing in farm fields a miles north without causing casualties.

Throughout last week, the army used loudspeakers to urge the militants to surrender or allow their families to leave the camp, but they have vowed to fight to the death.

The gunmen have recently been firing Katyusha rockets on nearby villages on an almost daily basis in what appears to be a new tactic to ease the army's pressure. A Lebanese teenager was killed and a young girl was injured last week in the rocket attacks.

Fatah Islam spokesman Abu Salim Taha also has warned they would send suicide bombers against the army if it continued its offensive.

The conflict with the militants is Lebanon's worst internal violence since the 1975-90 civil war. An undetermined number of militants — at least 60 — and more than 20 civilians have been killed in the fighting, according to Lebanese government and U.N. relief officials.