Nigeria's election commission has declared the party of outgoing President Goodluck Jonathan the winner of the governship election in the oil-rich Rivers State.
Nyesom Wike, from Jonathan's Peoples Democratic Party (PDP), won 1,029,102 votes, while Dakuku Peterside, of the All Progressives Congress (APC), won 124,896, the electoral commission said on Monday.
The APC, which previously controlled the state, described the result as "a rape of democracy" but the PDP said it was "a reflection of the people's confidence" in them.
Al Jazeera's Ahmed Idris, reporting from Abuja, said that the result was significant.
"Whoever gets the seat of the Rivers State is sitting on millions of dollars every month as oil revenues to the state and has a lot of control over that state."
Rivers is regarded as economically important to Nigeria as the states of Kano and Lagos, said Idris.
Jonathan lost the presidency to APC candidate Muhammadu Buhari in elections last month that were considered the freest and fairest yet in the country.
The parties faced off again on Saturday in elections for Nigeria's powerful state governors, who control budgets larger than those of some small nations.
Voting had to be extended into Sunday in some areas in several states including Rivers due to ballot box snatching and violence. In some, polls have been delayed even longer.
The electoral commission reported 66 instances of violence at polling stations, with the highest number in Rivers and other southern states.
Rivers state's defeated incumbent governor Rotimi Amaechi, a vocal critic of Jonathon, defected from the PDP to the APC two years ago and has been feuding with Jonathan ever since.
The state's information commission Ibim Semenitari said of the gubernatorial result: "What happened on Saturday was a rape of democracy. There was no election in Rivers.
"The PDP in connivance with INEC [Independent National Electoral Commission] and the security agencies merely wrote figures which they have churned out to the public," she told the AFP news agency.
She added: "We are going to challenge the results."
Local PDP spokesman Emmanuel Okha, however, said: "The people have spoken. We urge the APC to accept the results in good faith."
Source: Al Jazeera and agencies