President Umaru Yar'Adua has been hidden from public view since he fell ill
Senior Nigerian clerics have told the BBC they have met the country's ailing President, Umaru Yar'Adua, saying he had difficulty speaking.
He went to Saudi Arabia in November for treatment and, despite returning home recently, has not been seen in public.
The clerics said he had been able to shake hands and alert to what had been happening during their prayer meeting.
His absence created widespread alarm in Nigeria, prompting his deputy, Goodluck Jonathan, to assume executive powers.
The BBC's Caroline Duffield in Lagos says it is the first time anyone outside his family has spoken of seeing the president for many months.
Caroline Duffield, BBC News, Lagos
When Mr Yar'Adua fell ill, a charged atmosphere seized Nigeria's political world, and many people feared a coup.
An ugly power struggle began between the president's allies, who fought to keep him in office, and those who wanted power handed to Vice-President Goodluck Jonathan.
Shortly after Mr Jonathan was made acting president in February, Mr Yar'Adua was smuggled back into the country in an apparent attempt to grab back power. But it was too late - political support had shifted to the new acting president.
This latest twist - a carefully managed meeting, with an apparently recuperating president on display for chosen friends and clerics - will provoke yet more questions about what his allies plan to do next.
Ustaz Musa Mohamed, chief imam of the Abuja National Mosque, said the president had sat next to his wife, with an aide close by, at the Presidential Villa on Thursday evening.
He did not stand up or move about but shook hands with the clerics, raised his hands to join them in prayer and moved his lips to try to speak.
Ibrahim Datti Ahmed, chairman of the Supreme Council for Sharia in Nigeria, said the meeting lasted 10 mintues.
"We said the purpose of visiting him was to see if he actually exists," he told the BBC's Focus on Africa programme.
"Because there is a lot of speculation in the Nigerian press, that the president was not even in the country, that the president may have died or was not there.
"He was pale but certainly he was far far better than what we had been led to understand."
Mr Yar'Adua fell ill on 23 November last year and was flown to Saudi Arabia, where he stayed for three months.
His term of office expires in May 2011.
But amid the continuing uncertainty over his condition, it was announced last month that next year's presidential election could be brought forward by three months.