A presidential adviser says Nigeria has pardoned the former political benefactor of the nation's president, convicted of stealing millions of dollars while serving as a state governor.

Adviser Doyin Okupe said Wednesday that Nigeria's Council of States, a group headed by President Goodluck Jonathan, had approved the pardon for former Bayelsa state Gov. Diepreye Alamieyeseigha.

The decision, made in a closed-door meeting Tuesday, was greeted by outrage across Nigeria, an oil-rich nation long considered by activists as having one of the world's most corrupt governments. Nuhu Ribadu, a former police officer and corruption fighter in Nigeria, told The Associated Press that the decision was "the final nail" in the coffin for fighting graft in the country.