Mediators are hopeful of a deal to end fighting at the Nahr al-Bared camp.
Murr said the army had “destroyed all Fatah al-Islam positions”.
The comments came hours after Zeina Khodr, Al Jazeera’s correspondent in Lebanon, reported hearing machine gun fire and loud explosions at the camp.
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“When the defence minister talked about the operation, what he is talking about is the ‘new’ camp, [which is] the spillover from the official boundaries of Nahr al-Bared,” she said.
“There is a lot of confusion, especially since the Lebanese army has not released any official statement on a formal ceasefire.”
Murr said the camp would remain under a state of siege until remaining Fatah al-Islam fighters surrender.
He said Shaker al-Abssi, Fatah al-Islam’s leader, was unaccounted for, along with his deputy Abu Hureira.
“It’s not good enough to say Abssi was killed. If he is dead, give us the body.”
The army’s bombardment of the camp on Thursday came a day after Palestinian clerics acting as mediators presented a ceasefire deal to the Lebanese army.
By Thursday, no response had been given by the army to the mediators’ plan, one of the clerics said.
Khodr said one of the mediators informed her that Fatah al-Islam has agreed to an unconditional ceasefire.
The Lebanese army began operations in May against Fatah al-Islam in the wake of an attack on soldiers in Tripoli.
Fighting soon moved to the Nahr al-Bared camp, home to at least 30,000 Palestinian refugees.
Thousands of civilians in the camp fled amid fierce fighting between the army and Fatah al-Islam fighters entrenched in the camp.
At least 75 soldiers and 60 Fatah al-Islam fighters, as well as 20 civilians, are understood to have been killed in the weeks of fighting.
The Lebanese army has largely shelled the camp from its perimeter, observing a decades-old deal that prevents the army from entering Palestinian refugee camps.
Also on Thursday, a Lebanese prosecutor filed terrorism charges against 16 people suspected of involvement in commuter bus bombings that killed three people earlier this year, a judicial official said.
Nine of the 16 suspects charged by Saeed Mirza, prosecutor general, are in police custody, the official said.
The official, speaking anonymously, told Associated Press that all 16 belong to Fatah al-Islam, and include seven Syrians, a Lebanese man and a Palestinian woman.