MAHASTHANGARH, Bangladesh: When Abdus Sattar built his house in Mahasthangarh village in northern Bangladesh, he used materials that once laid the foundations of one of the world's oldest and greatest cities.

“I just shovelled into the ground, got these bricks and used them in my new house,” Sattar, 38, said.

“All three rooms of the house were made of the old bricks we found here within the village boundary.”

Mahasthangarh sits on what was once the ancient city of Pundranagar, built 2,500 years ago and, at its height, a renowned seat of learning whose monasteries attracted monks from China and Tibet and trained them to spread Buddhist teachings across south and east Asia.

The oldest archaeological site in what is now Bangladesh, the ruins of the fortified city are a major tourist attraction, but experts fear there will soon be little left for visitors to see.

The stripping away of sections of the ruins by residential encroachment and the casual looting of artifacts has threatened to erase the remains of a city that stood for millennia.

In May, the Global Heritage Fund, which promotes the preservation of historic architectural treasures around the world, listed Mahasthangarh among Asia's top 10 most endangered sites facing “irreparable loss and destruction”.

After a Bangladesh court handed down an order against illegal squatters early this year, houses like Sattar's began to be demolished, but archaeologists say much of the damage already done is now irreversible.

“The villagers destroyed some of the ruins so badly that it's now impossible to say what exactly was on this site,” said Shafiqul Alam, former head of the government's archaeology bureau.

“Many of the mounds described in cartographic sources have since disappeared,” said Alam.

Despite the court order, “the destruction continues...and villagers steal antiquities and bricks from the ruins to sell them in the market,” he added.

Antiquities found at the site suggest it was founded sometime in the 4th century BC and came to prominence during the great Mauryan dynasty that held sway over much of the Indian subcontinent until 185 BC.

Its golden period stretched from the 4th to the 7th century when, as part of the Gupta and Pala kingdoms, it was one of the largest cities in the world and a major centre of Buddhist teaching and studies.

The fortified area was still in use as late as the 18th century, but its influence had waned and it was eventually abandoned and consumed by the surrounding vegetation.

The site was rediscovered in 1879 by British archaeologist Alexander Cunningham.

The current chief government archaeologist at the site, M. Sadequzzaman, said encroachment began around 50 years ago and acknowledged that the early warning signs of serious degradation were ignored.

While some 500 houses were built inside the ancient city walls themselves — mostly using excavated materials — numerous villages sprang up in adjoining areas of equally important archaeological interest.

“The houses were built before the authorities could take a serious stand on conservation,” Sadequzzaman said.

“We were late to wake up. Had we tried to stop this before, we could have saved many valuable artifacts.”

Mahasthangarh's modern-day residents, like Sattar, believe they have been unfairly treated and deny that they took over the land illegally.

“My three children were born here,” Sattar said, pointing to the bulldozed remains of his home.

“If we were illegal encroachers, why did they allow us to build the house in the first place?”

Sattar said his father purchased the plot from a farmer and argued that scavenging on the site had always been an accepted way of making a living.

“Hundreds of houses were built from these old bricks. We didn't steal them, they are everywhere here. Everyone does it. Nobody barred us from doing it,” he said.

“Families have always picked things like beads, stones, coins that come to the surface after heavy rains. They are like endless resources, they never end,” he added.