PARIS, FRANCE -- From ancient mosaics to world-famous canvasses -- the trafficking of cultural treasures has gathered pace during the coronavirus pandemic with criminals increasingly conducting the trade online.

Lockdowns worldwide have left museums and archeological sites abandoned, often barely guarded, their artifacts vulnerable to thieves who often use social media platforms to sell on stolen goods.

"Two things COVID did -- One: people have more time. Two: People lose their jobs and need to find a way to make money," said Amr Al-Azm, co-director of the Athar Project which researches the digital trafficking of antiquities.

In 2019, the Athar Project counted 90 Facebook groups dedicated to trading in cultural treasures, with some 300,000 users.

Al-Azm said the number has since grown with some 130 such groups existing today -- many of them in Arabic language -- with users now estimated at around half a million.

The project has built "a catalogue of thousands and thousands of images" of antiquities up for sale on the platform, he said.

These include pharaonic coffins among a plethora of items from ancient Egypt, carved stone tablets from Iraq and Yemen, antique coins from Libya and mosaics and sculptures from Syria, according to the project.

"This is the incredible part of all this, this is not dark web... You don't have to be a hacker to find anything," Al-Azm said.

'OLD AS HUMANITY'

"The pandemic is a scourge" for efforts to rein in trafficking, said Ernesto Ottone, assistant director general for culture at UNESCO, the UN cultural agency.

On Saturday, UNESCO marks the 50th anniversary of its convention against the trafficking of cultural heritage.

But at the moment, Ottone said, there is "more looting, less information, fewer missions, fewer controls."

The coronavirus has hurt the fight against trafficking as conflict and the collapse of state authority continue in antiquities-rich nations such as Syria, Iraq, Afghanistan and Yemen.

"Looting of cultural heritage is as old as humanity itself. For as long as humans have been burying their dead, people have been coming and digging them up," said Al-Azm.

But he said it had now "accelerated" due to conflict as people return to their basic need of finding a way to survive.

Most illegal digs happen in the Arab world, sub-Saharan Africa and Latin America, according to experts.

"Often it is fragments of objects that are collected. So, in addition (to the loss of heritage) there is destruction," lamented Ottone.

'SIMPLE' THEFT OF VAN GOGH

Wealthy countries have not been spared: In the Netherlands in March, thieves stole the Vincent van Gogh painting "Parsonage Garden at Nuenen in Spring" from a museum closed due to the coronavirus.

Corrado Catesi of the WOA (Works of Art) unit at global police organisation Interpol lamented how simple the theft had been with people stuck indoors due to a lockdown.

"A man arriving with a motorcycle, opened the door, went away with the painting... It was very simple because (there was) no patrol," said Catesi.

Since Paris's Notre-Dame cathedral was severely damaged by fire in April last year, thieves have been trying to make off with stones from the site of the reconstruction.

According to Al-Azm, traffickers have in recent years shifted from traditional markets to the internet, particularly as social media has exploded in the Middle East.

Facebook, WhatsApp and eBay have all been employed in the trade.

Traffickers have flocked to Facebook in particular, aided by its algorithm which calculates what users are interested in so as to propose related posts and contacts.

Facebook in June announced a ban on antiquities trading and traders on its platform, a move the experts said they hoped it would enforce.

Interpol said it had no specific evidence of a surge in illegal excavations at protected heritage sites around the world.

"But we can assume that when all the energies go to the maintenance of health security -- when there are fewer patrols especially on archaeological sites often far from cities -- other areas are less covered," said Catesi.