"The party we put in place has failed and continues to fail our people, especially our young people", Abubakar - 71 on Saturday - said in a statement.
The Sun reported that Fulani Youth Association of Nigeria (JAFUYAN) has vowed to take a definite stand over the killings of their kinsmen in Numan, Adamawa State, "if Federal Government fails to act fast".
"After due consultation with my God, my family, my supporters and the Nigerian people".
Atiku had in a statement personally signed on Friday, said he was no longer comfortable with the APC, hence his resignation.
The PDP national publicity secretary, Prince Dayo Adeyeye, told newsmen at a press conference yesterday in Abuja that the plot was aimed at creating division and rubbishing the party.
You would recall too, that he stated that all the organs of the party would support him through the processes.
He said Abubakar was deceived into believing that the APC was a platform that would correct all the ills in the PDP.
Abubakar, who has sought the country's top job for three different parties at elections dating back to 1993, was one of a number of PDP members to quit before the last vote.
The PDP, however, said it would gladly welcome the former presidential candidate if he decides to return to the party, although Atiku said he wanted to take his time before taking the next step. Buhari, 74, is also from the north.