Although no official reason was given for the sack, observers said that it mights be connected with his disagreement with Obasanjo on certain policy matters.

The sack, which coincides with the day Obasanjo gave national awards to hundreds of Nigerians and foreigners who have contributed to national development, is with immediate effect, Oyo said.

Ayu, impeached as a senate president, was a former minister of Education, later, internal affairs before he was appointed to the environment ministry.