The alleged bribe is said to have been paid in the late 1990s when Halliburton subsidiary Kellogg, Brown and Root was part of an international consortium building a $4 billion gas plant in Nigeria.

"We are very serious about corruption now. The idea is to make bribe giving and bribe taking unprofitable, we want to stamp this out," President Olusegun Obasanjo's spokeswoman Remi Oyo said.

The probe could embarrass US Vice-President, Dick Cheney, who headed Halliburton from 1995 until his election.

US Justice Department on Wednesday confirmed that they had opened their own probe into the alleged bribe.

Anti-graft

Oyo said the case had been passed on to Nigeria's newly empowered anti-graft body, the Economic and Financial Crimes Commission (EFCC).

Though Nigeria has had little success in curbing endemic corruption, the EFCC in recent months has laid charges against a series of high-profile officials.

Last month five officials, including three former ministers, went on trial charged with accepting kickbacks from the French electronics giant SAGEM for a contract to supply ID cards.

And on Friday, Obasanjo sacked two former defence officials accused of embezzling more than $800,000 dollars and handed their case to EFCC.