Customs officials on the Indonesian tourist island of Bali said Friday that they've foiled an attempt to mail 24 elaborately decorated human skulls to the Netherlands.

The Customs Department said that cartons containing the skulls were intercepted on two separate dates in January. The skulls are believed to be culturally-significant artifacts from other parts of Indonesia.

They were labeled as manufactured from synthetic materials but found to be human after being examined by experts from the Balinese Cultural Heritage Conservation Center.

Customs official Ni Aniek said the skulls are probably from Papua, a Melanesian region that makes up easternmost Indonesia, and Kalimantan on the island of Borneo, home to indigenous Dayak peoples.

No one has been arrested.

The department said the cultural heritage center will decide what to do with the skulls.