Islamic State (IS) militants in Syria and Iraq are netting up to $US200 million ($263 million) per year from illicit trade in plundered antiquities, Russia's ambassador to the United Nations says.

The smuggling of artefacts, Russian ambassador Vitaly Churkin wrote in a letter to the UN Security Council, is organised by IS's antiquities division in the group's equivalent of a ministry for natural resources.

Only those who have a permit with a stamp from this division are permitted to excavate, remove and transport antiquities.

"Around 100,000 cultural objects of global importance, including 4,500 archaeological sites, nine of which are included in the World Heritage List of... UNESCO, are under the control of the Islamic State... in Syria and Iraq," Mr Churkin said.

"The profit derived by the Islamists from the illicit trade in antiquities and archaeological treasures is estimated at $US150-200 million per year."

The envoy from Russia, which has repeatedly accused Turkey of supporting IS by purchasing oil from the group, said plundered antiquities were largely smuggled through Turkish territory.

"The main centre for the smuggling of cultural heritage items is the Turkish city of Gaziantep, where the stolen goods are sold at illegal auctions and then through a network of antique shops and at the local market," Mr Churkin said.

Turkish officials were not immediately available for comment on the Russian allegations.

Russian-Turkish relations have been strained ever since Turkey shot down a Russian plane near the Syrian border last November.

Mr Churkin said jewellery, coins and other looted items are brought to the Turkish cities of Izmir, Mersin and Antalya, where criminal groups produce fake documents on their origin.

"The antiquities are then offered to collectors from various countries, generally through internet auction sites such as eBay and specialised online stores," he said.

Mr Churkin named several other internet auction sites that he said sold antiquities plundered by IS.

"Recently [IS] has been exploiting the potential of social media more and more frequently so as to cut out the middleman and sell artefacts directly to buyers," Mr Churkin said.

eBay did not respond immediately to a request for comment.

Reuters