BEIRUT (AP) -- Syrian rebels and residents of Aleppo struggled Saturday to contain a huge fire that destroyed parts of the city's medieval souks, or markets, following raging battles between government troops and opposition fighters there, activists said.
Some described the overnight blaze as the worst blow yet to a historic district that helped make the heart of Aleppo, Syria's largest city and commercial hub, a UNESCO world heritage site.
The labyrinth of narrow alleys lined with shops was once a major tourist attraction, but has been the scene of near-daily firefights and shelling in recent weeks after rebels who fought their way into the city two months ago pushed toward its center.
Amateur footage posted online by activists showed raging orange flames licking the wooden doors of shops as the wood crackled, and rebels using a small water hose as they struggled to put out the fire. Other videos showed a pall of smoke hanging over the city's skyline.
The fire started late Friday amid heavy government shelling and was still burning Saturday morning, activists said.
One Aleppo-based activist, Ahmad al-Halabi, estimated the blaze destroyed a majority of the shops in the district.
"It's a disaster. The fire is threatening to spread to remaining shops," said al-Halabi, speaking from the stricken area by telephone. He claimed Syrian authorities cut the water supply off the city, making it more difficult to put out the flames. He said rebels and civilians were working together to control the blaze with a limited number of fire extinguishers.
"It is a very difficult and tragic situation there," he said.
Once considered a bastion of support for Syrian President Bashar Assad's regime, Aleppo has in the last two months become the focus of the insurgency. Its fall would give the opposition a major strategic victory, with a stronghold in the north near the Turkish border.
Since the rebel offensive began in August, each side has controlled about half of the city and has repeatedly tried -- but failed -- to capture the rest.
Rebels launched Thursday what they said would be a "decisive battle" to drive Assad's forces out of Aleppo and fighting has since spread to wide swaths of the city.
The souks of Aleppo -- a maze of vaulted passageways with shops that sell everything from foods, fabrics, perfumes, spices and artisan souvenirs -- are a tactical prize for the combatants. They lie beneath the city's towering citadel where activists say regime troops and snipers have taken up positions.
Many of the shops have wooden doors, and clothes, fabrics and leather wares inside helped spread the fire, activists said.
The Aleppo souks are not the only Syrian cultural treasures to have fallen victim to the chaos of the country's uprising and the crackdown by the Assad regime.
Some of the country's most significant sites, including centuries-old fortresses, have been caught in the crossfire in battles between regime forces and rebels. Others have been turned into military bases, raising archaeologists' fears of damage.
Regime shelling of neighborhoods where the opposition is holed up has smashed historic mosques, churches and souks in the central Homs province and elsewhere the country. Looters have stolen artifacts from excavations and museums.
Rami Abdul-Rahman, who heads the Syrian Observatory, said it was not clear how the fire at the Aleppo market was started but also said a large part of the souks have been destroyed. The group relies on a wide network of activists on the ground.
The claims could not be independently verified because of limitations on the work of journalists in Syria.
Fighting continued in many parts of Aleppo Saturday and activists said at least three people were killed, including two rebel fighters. Syria's state-run news agency SANA said soldiers were pursuing military operations against armed groups in Aleppo and its outskirts, inflicting heavy losses on the "terrorists," the term used by authorities to refer to rebels.
In the Damascus suburb of Qudsaya, activists said the bodies of at least eight men were found who appeared to have been summarily executed, but the circumstances were not immediately clear.
The Syrian uprising began in March 2011 with largely peaceful protests but has since transformed into an insurgency and civil war that has defied all attempts at a diplomatic solution. Activists say more than 30,000 people have been killed.