Atiku Abubakar has formally joined the opposition Peoples Democratic Party (PDP), more than a week after he dumped the ruling All Progressives Congress (APC).
The former vice-president made the announcement on Facebook within the last hour.
He said the complaints he had with the PDP, under which he was vice-president from 1999-2007, had been resolved, laying the groundwork for his return.
Mr. Abubakar is expected to contest the 2019 presidential election.
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