It broke with a powdery snap. "This is human bone," he said.
Across much of Syria, the country's archaeological heritage is imperiled by war, facing threats ranging from outright destruction by bombs and bullets to opportunistic digging by treasure hunters who take advantage of the power vacuum to prowl the country with spades and shovels. Fighting has raged around the Roman ruins of Palmyra, the ancient city in central Syria, once known as the Bride of the Desert. And the Syrian Army has established active garrisons at some of the country's most treasured and antiquated citadels, including castles at Aleppo, Hama and Homs.
For decades Ebla has been celebrated for the insights it offers into early Syrian civilization. The scenes here today offer something else: a prime example of a peculiar phenomenon of Syria's civil war — scores, if not hundreds, of archaeological sites, often built and inhabited millenniums ago because of their military value, now at risk as they are put to military use once more.
Seen from afar, Ebla is a mound rising above the Idlib plain. It was first settled more than 5,000 years ago. It eventually became a fortified walled city whose residents worshiped multiple gods, and traded olive oil and beer across Mesopotamia. The city was destroyed around 2200 B.C., flourished anew several centuries later and then was destroyed again.
The latest disruption came after war began in 2011. Once rebels pushed the army back and into nearby garrisons, the outcropping upon which Ebla rests presented a modern martial utility: it was ideal for spotting passing government military planes.
And so Mr. Shibleh and several other fighters have been posted on the mound with two-way radios, to report the approaches of the MIG and Sukhoi attack jets that have repeatedly dropped bombs on cities and towns that have fallen from Mr. Assad's control.
"I keep a watch here," he said.
He and other members of his fighting group, which calls itself The Arrows of the Right, perform a dual duty. They say they also try to protect Ebla from full-on looting by thieves who want to sort through the place with earth-moving equipment, looking for artifacts to sell on the black market.
But even if the presence of The Arrows of the Right may have prevented the site from being scoured by bulldozer blades, it has brought harm. Ebla, occupied by even a few rebels, is suffering the effects of more traffic, damage and theft.
Mr. Shibleh himself digs on the ancient mound, and he has explored its underground passages. He led the way on this day into a series of ancient crypts.
"It is another country underground," he said, crawling on his chest through tunnels he clearly knew well.
In one section of tunnel, Mr. Shibleh found a large scoop-shaped piece of bone that appeared to be as light as a wafer. It had been part of a human head. "There were too many skulls," he said. "The cave here was full of them."
Those skulls, he said, are now gone — removed by artifact hunters and then thrown away.
Grave sites are potential spots to find jewelry or figurines, as some corpses were interred with offerings and possessions. This has made Ebla, like hundreds of other sites in a country that sometimes refers to itself as an open-air archaeological museum, a tempting spot for thieves.
Ebla's crypts have not been the source of its fame. In the 1960s and 1970s the city's prominence was restored and its name became well known among archaeologists when an archaeological mission led by an Italian, Paolo Matthiae, discovered the city-state's long buried archive, which held more than 16,000 stone tablets.
As they have been translated from cuneiform script, these records written on stone have shed light on the administration, trade, theology and life in a city from another time.
"Ebla was the most important and prominent kingdom in the era of 3000 B.C.," said Cheikhmous Ali, a Syrian archaeologist and an organizer of Protect Syrian Archaeology, an association that has been documenting damage and theft of Syrian antiquities.
The Ebla tablets, he said, along with another set found in Tal Baidar, "are considered the most ancient cuneiform texts in Syria."
The meticulous excavation of Ebla's ruins had continued in the decades since the tablets were unearthed, and layer by layer had turned up more artifacts. Archaeologists had left much of the site undisturbed, for careful sifting by future teams. They hoped for more finds.
That methodical examination has recently been replaced by crude digging and crime.
After Mr. Shibleh returned above ground, children were digging holes in the undisturbed sections of the mound, seeking more artifacts. Mr. Shibleh said some people also come to the site and haul away carloads of dirt from inside the tunnels; it is ideal, he said, for making the ceramic liner for bread-baking ovens.
Dr. Matthiae did not reply to e-mail messages. But after being shown photographs taken by The New York Times of the digging and intrusion into the crypts at Ebla, Mr. Ali was dismayed. He compared the continuing damage to the destruction of antiquities in Iraq after the American-led invasion in 2003.
"This is vandalism," he said. "Destroying the site by throwing the skeletons haphazardly here and there."
He added: "A whole civilization belonging to all humanity is being destroyed."
Mr. Ali and Maamoun Abdul-Karim, who leads the Directorate General of Antiquities and Museums in Syria, said that archaeologists on both sides of the war have appealed to the combatants to avoid using ancient sites for military purposes, and to protect ruins from vandals, looters and thieves.
The effort has had only a limited effect. "Even before the situation in Syria now, we didn't have very good control," Dr. Abdul-Karim said.
Dr. Abdul-Karim said his ministry has repeatedly asked the Syrian military to refrain from occupying ancient fortresses and historic places.
With military garrisons come almost casual damage — from foot and vehicular traffic, makeshift construction, digging for bunkers and sandbags, the use of open latrines, graffiti and more — as well as the risks to the ruins from bombs and bullets.
"To the soldiers, we try by all messages from 23 million Syrians, to say: 'Do not use the archaeology sites. It is our history, it is our heritage, it is for all people, it is for the world.' "
"We cannot refuse the army," he said ruefully. "The problem is that in some areas the fighting is very strong, and we can do nothing except to give the message."
