The chairman of Nigeria's anti-corruption Economic and Financial Crimes Commission, Nuhu Ribadu, has been ousted in a move criticized by anti-corruption campaigners. Gilbert da Costa in Abuja reports that Ribadu's term in office has been the subject of speculation in recent times.

The predominant view is that President Umaru YarAdua may have finally succumbed to pressure from politicians to stop the Economic and Financial Crimes Commission, or EFCC's corruption investigations.

Berlin-based corruption watchdog Transparency International routinely classifies Nigeria as one of the world's most corrupt countries.

President YarAdua came to power in May with a pledge to fight corruption without sparing anyone, no matter how highly placed.

The EFCC has been the most potent tool in the anti-corruption crusade since its creation in 2003.

The head of the Nigerian police, Mike Okiro, announced that President YarAdua has approved a compulsory one-year senior officer's training course for Ribadu, a ranking police officer. By that announcement, Ribadu is expected to be replaced as head of the EFCC in January.

Abuja based graft fighter Auwal Ibrahim Rafsanji, says the controversy that greeted the anti-corruption chief's removal illustrates major flaws in Nigeria's quest to stem endemic corruption.

"Past and present governments have not been able to institutionalize the fight against corruption around institutional approach," said Rafsanji. "And therefore it is built around individuals, which is not good for a nation that wants to fight corruption."

"A lot of Nigerians are also concerned that asking the EFCC chairman to go on a compulsory one-year course is not unconnected with the fact that there have been efforts to get him out of office since the beginning of this government. We are also concerned that this is coming at a time when high-profile cases of corrupt officials are being tried," he continued.

The EFCC is currently prosecuting seven former governors, including one of the country's most powerful politicians James Ibori, for corruption.

Campaigners had complained that Mr. YarAdua had been slow to arrest Ibori and other former governors accused of looting state funds.

The government had been accused of shielding Ibori from prosecution as a reward for his role in supporting the president's election campaign in April.

The EFCC, created by former president Olusegun Obasanjo, has been criticized for political bias against opponents of Mr. Obasanjo in the build-up to general elections earlier this year. Ribadu denies the charge.