Italy's Ferrero, the maker of Nutella chocolate spread, said on Wednesday it had bought Turkish company Oltan, one of the world leaders in the production and marketing of hazelnuts.

In a statement, the Piedmont-based Ferrero gave no financial details. It said Oltan had revenues of more than $500 million and five production plants exporting to the European Union and other important markets.

The deal is subject to regulatory approval.

A company spokesman did not elaborate beyond the statement when contacted by Reuters.

Hazelnuts are a key ingredient in Nutella and other Ferrero best-selling products such as Ferrero Rocher chocolates.

The family-owned and unlisted company, run by 89-year old patriarch Michele, had revenues of 8.1 billion euros ($11 billion)in the year to end-August 2013.