TRIPOLI, Lebanon - Lebanese security services have arrested three suspects and seized arms and ammunition in north Lebanon near the refugee camp hideout of Islamist fighters, security sources said on Friday.

They said senior Fatah al-Islam member Nabil al-Bustani, implicated in attacks on the army on May 20 that sparked the deadly weeks-long standoff, was arrested late Thursday in the port city of Tripoli.

Two 17-year-olds were also detained for possession of grenades which they said they had stumbled across in an apartment of Lebanon's second largest city, according to the sources.

In a sweep of Tripoli apartments, security services also seized shells and aging ammunition, while guns and more ammunition were found in an Islamist's home in Qalamoun, scene of a deadly raid on Fatah al-Islam fugitives last week.

In the Nahr al-Bared camp on Friday, the Lebanese army and the Al-Qaeda-inspired militants traded gunfire amid the blasts of shells and grenades on day 48 of their deadly showdown, an AFP correspondent said.

Lebanese troops have been closing the net around the militants holed up in the shattered seafront camp. Three civilians were taken out in an ambulance on Thursday in the first such evacuation in more than a week.

The Red Cross says relief teams have been denied authorisation to deliver relief supplies to the camp for more than two weeks.

The vast majority of the camp's original population of 31,000 have taken advantage of lulls in the fighting to flee, although hundreds of civilians running out of supplies are believed to be left cowering in their homes.

According to a count compiled from official figures and security sources, the battle has now claimed at least 173 lives, including 85 soldiers. -AFP