The documents are part of a lawsuit the Nigerian government filed on 7 June against one of the companies - Nigerian AGIP Oil Company, a subsidiary of Italy's Eni - and it was not immediately clear from the documents exactly how many of the companies Nigeria is suing.
Reached late Wednesday, Garba Shehu, a government spokesman, declined to comment.
The suit alleges that companies exported a total of 57 million barrels of crude to the US over the period and did not declare all of this to Nigerian government as required by law, according to the documents.
Eni
