Candidates of 30 registered political parties in Nigeria have begun wrapping up their campaigns with election rallies all over the country, ahead of legislative and presidential elections starting 12 April.
The main challenger to ex-military ruler President Olusegun Obasanjo is former military head of state, General Muhammadu Buhari of the opposition All Nigeria People's Party (ANPP).
Buhari has called on his supporters to be vigilant against election fraud
At his rally attended by thousands of supporters in the capital, Abuja on Tuesday evening General Buhari called on his supporters to be vigilant in order to avoid rigging of ballot boxes.
Thousand of supporters of the ruling party are gathering in the main Eagle Square in Abuja on Wednesday for a final rallly in support of President Obasanjo.
Tuesday's ANPP rally, with another planned for Wednesday in the northern town of Kano, coincided with an announcement by the police of progress made in the investigation of the death of a powerful and senior member of the party on 5 March.
Marshall Harry was murdered in his home and at the time, his death was described as an assassination.
But Police Commissioner Tafa Balogun produced five suspects to the press and declared the murder to have been part of a robbery and not an assassination, as was claimed by Mr Harry's party.
The PDP is expected to hold its final rally on Wednesday
The police said his killers had gone into his home to steal party elections funds, but when Mr Harry could not produce them, the men shot and killed him, the French News Agency, AFP reported.
Meanwhile delays over the handing over of an estimated 61m voters cards continue to mar the exercise.
The cards were to have been made available in registration centres across Nigeria from Tuesday.
But correspondents reported that in some parts of the country, the distribution has still not started and there are concerns that many people will not receive their voting cards before the election date.
In Lagos on Wednesday Inec officials told AFP they had yet to begin the procedure, and that the same was true for Kano.
The BBC's Yusuf Sarki Mohammed in Kaduna, northern Nigeria, reported on Tuesday that he saw scores of people waiting for officials from Inec to show up in virtually all the centres he visited.
On Monday, a spokesman for the Independent National Election Commission (Inec), Sam Okpo, said it had removed a total of 6m fraudulent names from the register of voters.
The national legislative elections are on 12 April to be followed by presidential elections on 19 April in which 18 people will challenge Mr Obasanjo for the presidency.
Nigeria is Africa's most populous state and was ruled by successive military dictatorships for 15 years before it was handed over to an elected government in 1999.
Some Nigerians are suspicious of the democratic process believing that the elections may not be as free and as fair as they would like.
Our correspondent says fear has been expressed that unless the distribution exercise is smooth and concluded successfully, a sizeable number of Nigerians might not vote.
Also on Tuesday, 16 smaller parties held a news conference in Abuja in which they called for the postponement of the polls saying Inec was not ready for the elections.