Nigerian officials have seized thousands of donkey penises that were about to be exported to Hong Kong, an official said on Thursday.

Sacks of the donkey male genitals were seized at the international airport in Lagos, Nigeria’s largest city, Sambo Dangaladima, the Nigeria Customs Service area commander, told reporters.

The consignment was “falsely declared … as cow male genitals (but) after due examination, my export officers discovered they were donkey male genitals,” said Dangaladima. A total of 16 sacks of the genitals were seized, he said.

An investigation has been launched to find out more information about the seized items, the customs service said.

Although the seizure of donkey genitals meant for export from Nigeria is rare, donkey skins are known to be frequently exported or smuggled out of the country. In July, the Nigerian customs seized $116,000 worth of donkey skins being smuggled into the country from neighboring Niger.

Nigeria is trying to curb the export of donkey skins which has drastically diminished the country’s population of the work animals, particularly in the north. Nigerian senators in 2021 proposed to ban the killing of donkeys and the export of their skins.