The Nigeria government says it will take tough action against politicians stirring up violence, after more than 100 deaths in religious riots.
Police were unable to quell the killings
Information Minister Frank Nweke said the authorities had heard of plans to provoke student demonstrations during the forthcoming census.
Nigeria's political temperature is rising ahead of next year's elections.
President Olusegun Obasanjo, a southern Christian, has fallen out with Muslim Vice-President Atiku Abubakar.
There are moves to change the constitution to enable Mr Obasanjo to contest a third term.
These are being strongly resisted by Mr Abubakar's supporters, especially in the mainly Muslim north.
Mr Nweke said the government would not hesitate to crack down on "selfish, unpatriotic, unprogressive and criminally minded persons", who he said were planning unrest.
"The identities of those who hide under the guise of religion to foment trouble and cause mayhem are also known.
Abubakar used to be a close ally of President Obasanjo
"They will be unmasked and punished according to the laws of the land," he added.
He warned that high position would not protect troublemakers against arrest or prosecution.
The clashes started with Muslim protests against the cartoons satirising the prophet Muhammad in the north.
These overlapped with anti-third term protests and dozens of Christians were killed, sparking revenge attacks in the south.
Elections are not due to take place in Nigeria until next year, but the ruling party will soon have to choose its presidential candidate.
The BBC's Elizabeth Blunt in Abuja says this has unleashed a round of furious - if secretive - political campaigning.
Proposals to change the constitution and allow the president to seek re-election went to public consultation last week.
If Mr Obasanjo were to stay on, our correspondent says it would dash the hopes of his Mr Abubakar, as well as a number of ambitious state governors - all of whom are keen to stand.
It would mean that the same region - the Yoruba south-west - could hold on to the presidency for another four years, when other regions and religions think it is their turn.
There is no love lost between the president and his deputy, and a number of Mr Abubakar's associates have already found themselves in trouble with the law or being investigated for financial malpractice.
Meanwhile, a national census is also stirring up strong feelings.
So keen is every regional and religious group to prove its numerical strength that what should be a simple administrative exercise has become another fiercely contentious issue which - in the words of the information minister - is now "heating up the polity".