She hinted that the pardons could have repercussions on U.S. assistance programs.
"We have made clear to the Nigerians that this puts a question mark on the kinds of work that we've been trying to do with them," she said. No sanctions or punitive measures have been taken, she said, "but we're continuing to look at what's appropriate."
Alamieyeseigha served as governor of Bayelsa state, in the heart of Nigeria's oil-producing southern delta, from 1999, when the nation became a democracy, through 2005. He was arrested in London after more than $1 million in cash was found in his home there. Alamieyeseigha escaped British authorities — Nigerian officials say he disguised himself as a woman — and fled to Nigeria, where he ultimately stood trial.
Alamieyeseigha's impeachment brought Jonathan, a little-known marine biologist who served as his deputy, into power. Jonathan as recently as a few weeks ago referred to Alamieyeseigha as "my boss" during an event in Lagos.
Analysts and activists routinely refer to Nigeria as having one of the world's most corrupt governments. The continent's most populous nation, Nigeria likely lost more than $380 billion to graft between 1960 and 1999, authorities have said. Meanwhile, just more than 60 percent of Nigerians earn the equivalent of less than $1 a day, according to a study published by the country's National Bureau of Statistics.
Since the closed-door meeting Tuesday where Jonathan decided on the pardon, Nigerians have reacted with anger on Twitter and elsewhere over the decision. An editorial Friday in The Punch newspaper of Lagos simply said: "The situation is becoming hopeless."
It wrote: "Ours is a government being run by narrow minds and harder hearts."
Associated Press writer Bradley Klapper in Washington contributed to this report.
The U.S. Embassy in Nigeria's Twitter account: www.twitter.com/USEmbassyAbuja
Jon Gambrell can be reached at www.twitter.com/jongambrellAP .