Nigeria's President Umaru Yar'Adua has returned home after three months' treatment in Saudi Arabia, officials say, but his condition is unknown.
A plane from Jeddah landed at Abuja airport in the early hours, where an ambulance was waiting on the tarmac.
Earlier this month, Vice-President Goodluck Jonathan became acting leader as fears mounted of a power vacuum.
Hundreds of people from Nigeria have written to the BBC with their thoughts about the current political situation in the country.
Below is a selection of some of the emails you've sent us.
President Yar'Adua left Nigeria in November, as everyone knows, but why was he flown into the country secretly in the dead of the night? Two things: either he is not back in the country - a ploy by power brokers to cause more confusion in the country that is already dead or it must have been his corpse that was flown in early Wednesday.
I am glad he is back but he should take his time and rest to recover fully. If I were him, I would resign and let Jonathan continue.
John Okon, Sugarland
It is good that the president is back but I don't know if he still has the strength to govern this nation. I should suggest he resign his office and go back to treat himself before he dies clinching to power. Goodluck is doing fine in his capacity as our president, therefore, if given an opportunity to serve, I think he will be credible.
Dr Samuel Eze, Imo, Nigeria
Since the president left, the country has been like a bunch of children with different mothers but the same father. The nation has been destabilised. Different institutions took autonomous decisions because no one can sanction them. I think his return has a selfish motive if he tries to return to power.
Somke Olisa, Abuja
His return has nothing to do with the progress of the nation because the nation was able to survive without him. Also, the state of his health was not declared and the fact that he was discharged doesn't mean he has recovered from his ailment. They should declare to the general public his present state, because our nation needs someone that is physically and mentally fit.
Ogunbeku Morolake, Ile-Ife, Nigeria
The absence of the president has left a big power vacuum in the country and ushered in a reign of power profiteering by a so-called kitchen cabinet. The endorsement of Mr Goodluck Jonathan was generally seen as a relief. His return is likely to throw the country into a state of ambivalence.
Dr Amah Joseph, Enugu, Nigeria
It's quite unfortunate to see leaders trying to hold onto power even when their health is suggesting otherwise. Yar'Adua's absence has resulted into some sort of economic stability. People wishing to keep him in power are just devoted sycophants who are only interested in what they will get from him.
Ugochukwu Samson, Owerri, Nigeria
The president's presence made no impact and his absence brought no difference. Now, his coming back will change nothing. I just hope that he doesn't think of returning to the presidential seat. Nigeria is sick and very sick of having a sick president.
Chris, Ota, Nigeria
I think that the president's return to the country is one of the best things to have happened this year because it will bring peace and unity and also prevent a change of government. I wish Mr President a quick recovery.
Ibemere Tochukwu, Nigeria
Business is going on as usual, as the citizens wait expectantly for events to unfold. This turn of events is seen as a desperate deed by the wife and those northerners who're trying to perpetuate their stay in power.
Ideobi, Enugu, Nigeria
I believe the president's absence has retarded the dwindling development of the country. Ever since the absence of the president, there has been a problem with the supply of power and petrol scarcity in the country. Therefore, it was right to install Goodluck as the new president.
Abd'razaq Kayode, Ilorin, Nigeria
This sounds so extremely comical! How can a president sneak out of the country for three months and remain in communication and finally sneak back again in the wee hours of the night? As much as we sympathise with him over his illness, governance must go on. No single individual or group is greater than Nigeria. Enough is enough!
Emeka Oguike, Nigeria
It's good riddance to bad rubbish. The man is incapacitated but the Northern Cabal is blindly holding on to him and his presidency. The implications are obvious. Nigeria will never progress as this goes on. It is one step forwards, two steps backwards. The greedy "hawks" will always have their way as long as they keep impotent and inactive Yar'Adua there. Nigeria needs a new lease of life.
Kenny Davis, Lagos
The absence of our president has led the masses into unbearable situations. Before he went for treatment things were better than they are now. There's economic breakdown, failure in generating power, deregulations and corruption and selfishness. Now that he's back, he can't rule the country anymore.
Ademola, Ibadan, Nigeria
The sudden story of Yar'Adua's return is a political gimmick by power drunk northern Yar'Adua loyalists to remove Goodluck from his seat as acting president. Yar'Adua is not fit to govern.
Mike Onyekwelu, Onitsha, Nigeria