Nigeria's human rights chief is demanding that the government prosecute those responsible for the killings of at least 97 people in election-related violence in southern Rivers State.

The chairman of the National Human Rights Commission, Chidi Odinkalu, said in a Twitter message that the assassins belong in jail and Nigeria should end impunity for political violence.

Odinkalu chaired a commission of inquiry that in May published the names of 117 people it said should be prosecuted for crimes from killings to burning houses in the run-up to the March presidential and April governorship elections that brought Nigeria's first democratic change of government.

A tribunal Saturday nullified the election won by Rivers State incumbent Gov. Nyesom Wike, raising more tension in the oil-rich state.