The U.S. government has asked South Korea to arrest a brother of former U.N. Secretary-General Ban Ki-moon on charges that he engaged in a bribery scheme to carry out the sale of a Vietnamese building complex, a U.S. prosecutor said on Friday.

During a court hearing in federal court in Manhattan, Assistant U.S. Attorney Daniel Noble said that a request had been made for the arrest of Ban Ki-sang, who was an executive at the construction firm Keangnam Enterprises.

Noble said the United States plans to seek his extradition "but as of yet, he has not been apprehended."