US prosecutors have accused Jason Steph, a former manager at Willbros Group, and others of bribing Nigerian officials between 2003 and 2005 to help the Houston-based company secure a $387 million contract to build a gas pipeline.
Nuhu Ribadu, chairman of Nigeria's Economic & Financial Crimes Commission, said it was co-operating with US law enforcement agencies on the case.
"You will definitely see the outcome of our own investigations and if it means there will be indictments in Nigeria then so be it, there will be.