A private American collector has returned a dozen ancient artefacts to Thailand as the south-east Asian country presses for the return of other treasures that were taken abroad.

Culture minister Vira Rojpojchanarat said the artefacts were given by Katherine Ayers-Mannix to the Thai Embassy in Washington, DC, which shipped them back to Thailand.

The items are believed to have mostly come from a prehistoric civilisation dating back more than 4,000 years that was centred around Ban Chiang, in what is now Thailand’s north-eastern province of Udon Thani.

Mr Vira, speaking at a news conference in Bangkok, said Thailand is seeking the return of other items that were taken illegally from the country which ended up in US museums, and has been gathering evidence to back its claims.

Thai officials have been tracking artefacts such as nine ancient Buddhist relics that are on display at the Norton Simon Museum in California, as well as 17 other relics on display at the Honolulu Museum of Art in Hawaii.

Artefacts
This clay vessel and a dozen other ancient artefacts have been returned to Thailand by a private American collector (AP)

He said 14 out of the 17 items in Hawaii have been confirmed to have Thai origins, and that information has been forwarded to the US department of homeland security as part of Thailand’s quest to have them returned.

Anandha Chuchoti, director general of Thailand’s fine arts department, said Thai officials are also providing evidence to prove that two ancient lintels on display at the Asian Art Museum in San Francisco were stolen from ancient temples in Thailand’s north-eastern provinces of Buriram and Sa Kaeo.

“We want to send (information) to confirm that these lintels have Thai origins and had made their way out of the kingdom illegally,” the director general said, adding that the two lintels are no longer on display as the claims are being considered.

In 2014, the US government returned 554 ancient artefacts, mostly pottery, that had been taken from Ban Chiang, a Unesco World Heritage Site.

The pieces were recovered in a 2008 raid on the Bowers Museum in Santa Ana, California, which agreed to return the items to Thailand in exchange for no criminal charges for its staff.

The raid was part of a multi-year investigation in which three other California museums and two private art dealerships were also raided. Several people accused of being part of a network smuggling art from south-east Asia were arrested.