The government late Sunday released a photograph of President Muhammadu Buhari purportedly meeting a group of officials in London, where he has been treated for an unknown illness.
The image showed the 74-year-old president sitting at a table laid with fruit and soft drinks with senior members of his party on Sunday, according to a statement.
It is the first image of Buhari to be released since he travelled to the U.K. for medical reasons on May 7.
The meeting came amid mounting concerns about his health and opposition calls by him to step down. Buhari's medical leave -- the second this year -- has raised doubts about his ability to contest for a second term in 2019.
At least three court cases have been filed to compel parliament to declare Buhari unfit to hold office.
It was the second meeting Buhari had with officials from Nigeria. Earlier this month, Acting President Yemi Osinbajo visited him but no photograph was released.
"Party delegation spent more than an hour with President Buhari over lunch and it was very clear from the discussions that he followed developments at home very closely," presidential spokesman Femi Adesina said in a statement.
"When asked to react to all the negative things being said about him, the president just laughed, describing such negative reports as lies.
"Governor [Rochas] Okorocha said President Buhari was completely unperturbed by the cocktail of lies. He, instead, sent his best wishes to Nigerians."
The delegation consisted of members of Buhari's All Progressives Congress, including governors and ministers. Okorocha referred to talk of the president's incapacity as "fake news".
Buhari would return to Nigeria "as soon the doctors give him the green light," the statement added.
His first medical leave began in January and lasted nearly two months.
