New York - The United States has returned 11 cultural artefacts to the government of Nigeria. Authorities said on Thursday that French customs officials tipped off the US in April 2010 about a shipment headed to New York's Kennedy Airport. The 10 Nok (nahk) statues and a carved tusk were seized from a Manhattan gallery owner, and an investigation determined they were bona fide antiquities. The artefacts are to be displayed in Nigeria's national museum. Nok statues are about 2 000 to 2 500 years old, among the oldest sculptures in West Africa. They were first unearthed in 1943 at a tin mine near the village of Nok in central Nigeria. Homeland Security investigators say two Nok statues and a carved ivory tusk were previously seized at Chicago O'Hare International Airport.