Lebanese soldiers and diehard Islamist militants entrenched in Nahr al-Bared refugee camp fought gunbattles on Sunday after at least 17 people were killed in an operation to storm rebel positions, and mediators announced a setback in efforts to broker a peaceful end to the 22-day standoff.
As the showdown entered its fourth week, an army officer said the high casualties were suffered in clashes, often at close quarters, on Saturday, which also wounded another 40 soldiers.
The army, which has encircled Nahr al-Bared, tried to push into the Palestinian refugee camp in north Lebanon and overrun positions held by Fatah al-Islam militants, which has snipers posted on rooftops.
Amid sporadic fighting on Sunday, the army's spokesman said soldiers had advanced 50 meters (yards) inside the camp and were clearing booby-traps from four buildings where the Islamists had been driven out.
The Islamists' spokesman Shahine Shahine told AFP that four of their fighters had been killed and six wounded in beating back the army advance.
Two Palestinian civilians, whose bodies were evacuated by the Red Crescent on Sunday, also died in the previous day's shelling of the mostly deserted camp, rescue workers said.
The weekend's bloodshed brings to 123 the number of dead since clashes erupted on May 20. They include 58 soldiers and 50 members of Fatah al-Islam.
Lebanese authorities say the fighting was sparked by raids on Fatah al-Islam hideouts in Tripoli following a bank robbery, after which the militants attacked army posts.
Mediation not working
The fierce fighting came as a group of Muslim religious leaders that has been shuttling between the two sides in a bid to broker a peaceful end to the siege was due to meet army chief Michel Suleiman.
A negotiator, Sheikh Fathi Yakan, said on Sunday: "It's total impasse. The international leaders of the Al-Qaeda network have taken over... and the Fatah al-Islam members are refusing to give up."
The mediators said they had suffered a setback Friday when they were only able to see Shahine, not more senior Fatah al-Islam leaders.
"Something is going on within Fatah al-Islam ranks," delegation member Yakan said. "Their leaders are no longer visible. We were only able to meet a junior official while their top leaders like Shaker Abssi have gone to ground and aren't talking."
However, another Fatah al-Islam spokesman, Abu Salim Taha, told AFP the mediation was not welcome as it was preconditioned on the Islamists turning themselves in.
"We maintain control of our positions despite the pounding from the army's artillery," he added.
Troops have so far refrained from penetrating the camp on the Mediterranean coast north of Lebanon's second city of Tripoli, where some 4,000 civilians are still believed to be trapped by the fighting.
By longstanding convention the army does not enter Lebanon's 12 refugee camps, leaving security inside to Palestinian militants.
However, Prime Minister Fuad Siniora hinted Friday that those arrangements might have to be reviewed in light of the failure of mainstream Palestinian groups to deal with the Islamist threat.
"Fatah al-Islam's entry into the Nahr al-Bared camp shows the failure of the Palestinians' autonomous security system," Siniora told France 24 television.
The Western-backed premier, a staunch opponent of Syria, also implicated intelligence agents from Lebanon's once dominant neighbor in sponsoring the militants.
"Undoubtedly ... there is a link between them and some of the Syrian intelligence services," he said.
Meanwhile, French envoy Jean-Claude Cousseran arrived in Beirut on Sunday to follow up an invitation by the French foreign ministry for leaders across Lebanon's political divide to attend informal fence-mending talks on the country's future later this month.