Nigeria's Buhari to return from UK medical leave on Friday

President Muhammadu Buhari

Nigeria's President Muhammadu Buhari will return to the West African nation on Friday after extended medical leave in Britain, the presidency said on Thursday.

Buhari, 74, left Abuja on Jan. 19 for treatment in Britain. He had originally planned to stay 10 days but stayed longer to rest after consulting his doctors.

Officials have refused to disclose his illness, triggering fierce speculation in Nigerian media and on social media.

"President Muhammadu Buhari is expected to return to the country tomorrow, Friday March 10, 2017," the presidency said in a statement.

"President Buhari expresses appreciation to teeming Nigerians from across the country, and beyond, who had prayed fervently for him, and also sent their good wishes," it added.

The statement gave no medical details.

The presidency had earlier on Thursday published pictures of a smiling Buhari meeting the Archbishop of Canterbury, Justin Welby, in Abuja House, part of the Nigerian High Commission in London.

No official pictures of Buhari's meetings in London had been posted since Feb. 15.

The government had sought to allay concerns of a void at the helm of Africa's biggest economy by stressing that Buhari had given Vice President Yemi Osinbajo full powers as acting president during his leave.

Osinbajo, a lawyer, held in Buhari's absence cabinet meetings and finished work on an economic reform plan needed to secure a World Bank loan to help plug a deficit caused by low oil revenues.

The central bank also devalued the naira for retail customers two weeks ago.