The Atiku Abubakar Presidential Campaign Organisation has said the emergence of President Muhammadu Buhari as the candidate of the ruling All Progressive Congress is fraudulent.
It said Mr Buhari was the only candidate cleared by the APC to contest its primary, "yet, a coalition of five aspirants are (is) challenging his victory. That alone tells Nigerians his emergence is fraudulent".
The group, reacting to a similar attack on Mr Abubakar by the president's campaign team also said it is not surprised at the criticism.
The organisation, which disclosed this in a statement made available to PREMIUM TIMES, said the emergence of Mr Abubakar means the coming end of APC's "ignominious reign".
Mr Abubakar will be the main challenger of the incumbent president at next year's polls after clinching the presidential ticket of the main opposition party, the Peoples Democratic Party at its convention in Port Harcourt over the weekend.
The Buhari Campaign Organisation, on Sunday, questioned the credibility of the former vice president's emergence at PDP's flagbearer.
In a sarcastic congratulatory message to Mr Abubakar, the organisation said the allegations of massive vote-buying at the primaries raises credibility issues and the kind of values he (Abubakar) brings into the politics of Nigeria.
The Director, Strategic Communications, of the organisation, Festus Keyamo, also flayed Mr Abubakar further challenging his antecedence and integrity while in office.
But the Abubakar group has responded challenging the APC to look inwards rather than criticise its own exercise.
It questioned the process of the APC's primaries recalling that even the wife of the president, Aisha Buhari condemned the primaries of the ruling party. It said in its own case, "the eleven other aspirants of the PDP accepted Atiku's victory".
Mrs Buhari on her Twitter handle had earlier condemned the primaries of the APC saying the irregularities that marred the process had put a credibility mark on the outcome.
"We ask, how can the Buhari Campaign Organisation disparage the PDP primary that produced His Excellency, Atiku Abubakar, when even the President's own wife, Aisha Buhari, has condemned the APC's primary? Not only did Mrs Buhari condemn APC's primaries, she described them as 'unfair' and lacking in integrity. Who can know President Buhari better than his wife?
"President Buhari was the only candidate cleared by the APC to contest its primary. Yet, a coalition of five aspirants is challenging his victory. That alone tells Nigerians his emergence is fraudulent."
The group said even the president's former running mate, Tunde Bakare, praised the emergence of Mr Abubakar, whom he described as an "Eagle and a cosmopolitan Wazobia (unifying) politician".
The group also said if the Mr Abubakar "is the most investigated politician in Nigeria," as claimed by the president's team, it was worrisome that it had not found it necessary to arrest the politician since it came into power.
The group said Nigerians "who have suffered under the present administration", will readily vote for Mr Abubakar.