BENGHAZI, Libya — A massive explosion ripped through a major weapons depot for Libyan rebels outside this rebel-held city Friday, killing dozens and possibly dealing a major blow to the ongoing battle to topple Moammar Gadhafi.
The explosion leveled nearby buildings and overturned cars in the town of Rajma and could be felt throughout this city. Flames shot hundreds of feet into the air.
Medical officials said the death toll was unknown, but would be high. Other reports said at least 60 had been killed, including 17 firefighters who reportedly died trying to extinguish the flames.
"We've got pieces, arms and legs, so we don't know how many people were killed," said an official at the Harwadiya Medical Center, one of the facilities where casualties were rushed for treatment.
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"There must be a lot of dead not discovered yet in the nearby houses because the explosion was so big. You should look for bodies outside the base," said Bashir Ahmed Madani, 26, who was guarding the military camp entrance that led to the weapons depot and spoke from his hospital bed, where he lay covered with a bloodied pre-Gadhafi Libyan flag.
It was unknown what caused the explosion. Pro-Gadhafi war planes had tried to bomb the depot twice in recent days, without success, but there were no reports of air attacks when the explosion occurred at about 7 p.m. local time.
Whatever its cause, the timing of the blast couldn't have been more inopportune for the rebels.
For the first time since they took control of much of eastern Libya, the rebels on Friday had gone on the offensive, seizing the key oil town of Ras Lanouf on Libya's coastal highway, and moving their frontline 70 miles to the west in what appeared to be the first step in a long-promised march to Tripoli, where Gadhafi forces are in firm control.
Whether the rebels would be able to continue their westward movement without the depot was unclear. On Wednesday, the depot had been a primary source of arms for the ragtag rebel army that rushed from Benghazi to the port city of Brega to rebuff an assault by Gadhafi loyalists.
In the west, Gadhafi forces continued their siege of rebels in Zawiya and Misrata as the battle for control of Libya became a two-front war.
In Zawiya, Gadhafi forces blocked injured rebels from entering a hospital. In Misrata, residents finally gained enough ground to recover the body of a fighter killed four days ago.
Fighters in both towns said they're running out of ammunition for their Kalashnikov assault rifles and other small weapons as they faced pro-Gadhafi forces equipped with tanks and artillery.
Residents said Zawiya had been surrounded by Gadhafi forces on the south, east and west in the morning but that rebels had pushed them back. But the forces came back by afternoon through the west, eventually planting themselves in front of the hospital.
Tarek Zawi, a rebel using a nom de guerre for security reasons, said Gadhafi's forces had killed one of two top rebel commanders. Heavy machine-gun fire could be heard in the background as he spoke by telephone.
He said rebels had seized four trucks mounted with high-caliber machine guns on Thursday, but that there appeared to be little hope of new ammunition supplies, because neighboring towns remained loyal to Gadhafi.
Government forces "are shooting in front of the hospital, so our injured can't get to the hospital," Zawi said.
A doctor reached by phone at the city's main hospital said at least 10 were killed and another 50 wounded, but said other wounded and dead were beyond the reach of medical personnel.
In Misrata, residents said pro-Gadhafi forces had remained near an air base outside the town from 11 p.m. Thursday until 7 a.m. Friday, but hadn't tried to seize the city. When the troops withdrew, residents said they recovered the body of a dead fighter at the air force base and buried it.
The explosion at the Rajma depot overshadowed what had been a major rebel success — the seizure and occupation of Ras Lanouf, Libya's largest oil production center, which at its peak produces about 220,000 barrels of oil a day.
In taking control of the town, the rebels had moved their frontlines 70 miles west of Brega, where they'd repulsed a Gadhafi attack on Wednesday.
A spokesman for the military council in Benghazi, Khaled Sayah, said the rebels' next goal is Ben Jawad, 35 miles further west.
"Maybe in a couple days we will be in Sirte," he said, referring to Gadhafi's hometown, a key loyalist stronghold that the rebels must take if they're to make their way to Tripoli, still 250 miles away.
The geography of the cities up for grabs made fighting far easier for rebel forces in the liberated east than those around the capital, Tripoli.
In the east, rebel fighters can move tanks and weapons from one battle zone to the next along a well maintained highway that allows confiscated tanks from as far as Tobruk, near the Egyptian border, to be brought to bear in cities hundreds of miles away.
Rebels took advantage of that ability on Friday to station tanks in a string of cities that had recently seen pro-Gadhafi attacks, including Ajdabiya, Brega and Ageila.
"Our youth are heading west," said Osama Orafee, a former soldier who's positioned himself at the gate of his hometown, Ajdabiya. "They are taking heavy weapons with them."
The challenge is much different nearer the capital, where rebels in Zawiya and Misrata cannot depend on outside help for fighters, weapons or ammunition.
"All we have are the weapons we captured when we took over the city," said Abdel Baset Ahmed Abu Munzeerak, a spokesman for the newly-formed council governing Misrata.
Despite that, he said he remained hopeful that the rebels would prevail, especially if the West imposed a no-fly zone, keeping Gadhafi from using his air force.
"We are waiting for a no-fly zone," he said.
In the meantime, "we are fixing a lot of weapons and machine guns, but it is going to take time. We can defeat him, but it is going to take time."
In Benghazi, there was also hope that a no-fly zone would be imposed. Tellingly, a large "No Foreign Intervention" sign that had hung over the courthouse in the early days of liberation had been taken down.
Essam Gherani, a spokesman for the newly formed provincial council responsible for the east, said he now would welcome precision strikes at Gadhafi and his forces.
"If these bastions were hit, this would be done in 24 hours," Gherani said. "The will (of the rebel forces) is there, but the means is something else."
(Hannah Allam in Cairo and Jonathan S. Landay in Washington contributed to this article.)
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