A lentil originally from the Nong Hong Sanctuary in Thailand is displayed during a ceremony to return it and another stolen hand-carved sandstone lintel dating back to the 9th and 10th centuries to the Thai government on May 25, 2021, in Los Angeles. The 680-kilogram antiquities had been stolen and exported from Thailand — a violation of Thai law — a half-century ago, authorities said, and donated to the city of San Francisco. They had been exhibited at the San Francisco Asian Art Museum. (ASHLEY LANDIS / AP)

Thailand held a welcoming ceremony on Monday to mark the return of two ancient hand-carved artefacts that were stolen decades ago and smuggled out of the country to the United States.

Thailand had informed the United States in 2017 that two 680 kg Khmer-style stone carvings, which date back to the 10th and 11th century, had been stolen

The two 680 kg Khmer-style stone carvings had been on display at the Asian Arts Museum in San Francisco, which was required to forfeit them when a settlement was reached in February between the US government and San Francisco authorities.

Thailand had informed the United States in 2017 that the lintels, which date back to the 10th and 11th century, had been stolen.

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"Today is the day that they are finally returned to their home country and displayed here," Thai culture minister Itthiphol Kunplome said at the Bangkok ceremony.

Thai and US officials participate in a ceremony to return two stolen hand-carved sandstone lintels dating back to the 9th and 10th centuries to the Thai government on May 25, 2021, in Los Angeles. (ASHLEY LANDIS / AP)

The sandstone lintels were once parts of the structure of two religious sanctuaries in Thailand's northeast. The government will assess whether they can be returned to their original locations.

"This is a legal battle that has set an excellent example for the museums that still own Thai artefacts illegally because they know they will lose the case," said Tanongsak Hanwong, who located the artefacts and pushed for their return.

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"Many museums have chosen to reach out to begin the return process instead of going into the legal process."