Nigerian lawmakers have called on the president to cancel a pact with the United States that prevents Nigeria from surrendering suspected American war criminals to the International Criminal Court.
A resolution passed by Nigeria's Senate says the agreement violates the country's constitution.
Lawmakers reminded President Olusegun Obasanjo the pact has failed to meet a constitutional requirement that parliament must enact international treaties into law.
Senate resolutions are non-binding.
The United States has negotiated treaties with many nations to keep its citizens from falling under the International Criminal Court's jurisdiction.
The Bush administration has refused to ratify a treaty creating the Hague-based court, asserting U.S. troops abroad could be targeted for politically motivated prosecutions.
Some information for this report provided by AP and Reuters.