President Muhammadu Buhari's whereabouts appears shrouded in mystery, two days after he left Washington following a bilateral meeting with President Donald Trump.
The president was expected in Nigeria on Wednesday.
Mr Buhari's official aircraft, Eagle One, left Joint Base Andrews military airfield in Washington on Tuesday morning and arrived in London at 9:42 p.m., according to Flight Radar 24, which tracks air traffic across the world.
But as at 10:00 a.m. Thursday, the aircraft was still in London amidst unclear circumstances.
An April 27 State House press release which announced Mr Buhari's scheduled take-off from Nigeria on May 28, did not say he would stop by in London.
The statement only gave highlights of the president's engagement while in the U.S.
Mr Buhari arrived in Washington on April 29 and had a series of bilateral meetings with Mr Trump, including a working launch and a joint press briefing.
Mr Buhari then left the American capital in the morning of May 1, according to one of his media aides. Bashir Ahmad, said the president was on his way to Abuja, Nigeria.
President @MBuhari has departed Joint Base Andrews Airport for Nnamdi Azikiwe Airport, Abuja after a Working Visit to Washington DC where he had a bilateral talks with US President @realDonaldTrump, and met with a group of business executives. #PMBinDC pic.twitter.com/QgFgDYN2Sv
- Bashir Ahmad (@BashirAhmaad) May 1, 2018
There was no official announcement updating the nation about a possible change of route for the president.
PREMIUM TIMES reached out to senior presidential spokespersons Femi Adesina and Garba Shehu to clarify the president's whereabouts.
None of them responded to phone calls and text messages about the matter as at Thursday morning.
Mr Buhari was treated for an undisclosed ailment in London for months between 2016 and 2017, .
Since returning to work, most of the president's foreign trips have been planned with connections through London, officials say.
The presidency has not given details of Mr Buhari's health, and it is not clear whether he was billed for medical evaluation in the UK during his current trip.