Spanish police said Monday they have seized centuries-old gold artefacts worth over 60 million euros ($64 million) that were stolen and taken out of Ukraine illegally.

The 11 pieces, including necklaces, bracelets and earrings,  were displayed at a Kyiv museum between 2009 and 2013, and were smuggled out of Ukraine before 2016, police said in a statement.

"The seized peices -- gold jewellery of great historic and economic value -- had been stolen and exported illegally from Ukrain and were going to be sold in Madrid," the statement added, noting items dated from between the 8th and 4th centuries BC.

Three Spanish and two Ukrainian nationals -- one of them an Orthodox Church priest -- were arrested as part of the operation, which was carried out with the help of the authorities in Ukraine as well as Albania, Bulgaria, Cyprus and North Macedonia.

Police said the artefacts had forged documents in English, Ukrainian and Spanish to make it look as if they belonged to the Ukrainian Orthodox Church.

"These are pieces that cannot be sold through the usual legal channels, such as auction houses," said police spokeswoman Ana Ramon.

Police began their investigation in 2021 after one of the pieces -- a gold belt with rams' heads -- was sold to a businessman in a private sale in Madrid.

This led investigators to the other 10 artefacts which police seized last month from the suspects.

The pieces are being studied by Spain's National Archaeological Museum and the country's Cultural Heritage Institute.

al/ds/jm