President of Nigeria Muhammadu Buhari waits to address the United Nations General Assembly at UN headquarters in New York City on Sept. 20, 2016. Getty Images

After spending the past seven weeks abroad with an unidentified illness, Nigerian President Muhammadu Buhari officially returned to his country Friday. Buhari, 74, gave a nine-minute speech upon his arrival, adding that he'd never been "so sick" as in recent months, but did not disclose his ailment, BBC News reported.

Buhari was set to take back the reins from Vice President Yemi Osinbajo, who's been in control since Jan. 19, on Monday. "I deliberately came back towards the weekend so that the vice president will continue and I will continue to rest," the president said, according to Al Jazeera. "All I will need is to do further follow-ups within some weeks."

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Buhari's unexpected, extended absence meant he was returning Friday to a nation of critics. Nigerians have expressed frustration that the president didn't tell them what was happening with his health amid an economic crisis sparked by decreases in oil prices, BBC News reported. People have cited the health care as a reason Buhari, elected in March 2015, was unfit to lead Nigeria.

That said, at least one resident of Kano told NAIJ Friday he was happy Buhari was alive and well.

"I have no words to express my happiness and gratitude to God for bringing him back to the country safety and in good health," Mukhtar Dahiru-Rigachikun said. "The only thing I want to add is that Nigerians should thank God for returning him safely and those wishing him dead should desist from such wishful thinking."

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The next general election was recently set for February 2019. In the meantime, Buhari's disappearance could mean his role will permanently change.

"Nothing much will change in terms of governance; the vice president is still very much likely to be going around more frequently than Buhari," policy expert Olusegun Sotola told Bloomberg. "I see more activities coming from Osinbajo; Buhari will stay more in the background."