An immunisation programme was launched last month by the United Nations in the northern city of Kano in an attempt to wipe out the disease.

The World Health Organisation (WHO) says it is using safe, licensed products, but stresses that it will not administer a medicine without consent.

Suspicions

The WHO campaign aims to eliminate the crippling disease in Nigeria by the end of the year, and in the other nine countries where it is found by 2005.

Health officials believe this is feasible after a coordinated 14-year global campaign brought down cases across the world by 99.8%, from 350,000 in 1988, to 600 in 2001.

But some Muslim clerics are not convinced and have discouraged people from having their children vaccinated.

"I am sceptical and apprehensive about the polio campaign given the desperation and the rush of the sponsors, who are all from the West," a young scholar, Muhammad bin Uthman, told the French news agency AFP.

"They claim that the polio campaign is conceived out of love for our children.

"If they really love our children, why did they watch Bosnian children killed and 500,000 Iraqi children die of starvation and disease under an economic embargo?" he asked.

Pfizer scandal

The opposition of radical clerics is partly motivated by grievances against pharmaceutical companies.

"The Pfizer drug test in 1996 is still on our minds. To a large extent, it shaped and strengthened my view on polio and other immunisation campaigns," said Mr bin Uthman.

At the time, the US company had used an untested drug on children to fight an epidemic of bacterial meningitis in the Kano area.

Lawsuits have since been lodged against Pfizer in the United States and in Nigeria, alleging that the drug trial was illegal and that it killed 11 children and left 200 others disabled.

Aids connection

Other explanations have been given by those opposed to the vaccination programme.

A cleric told the BBC's Focus on Africa programme that he was worried the polio vaccine might have been responsible for the spread of the Aids virus in east Africa.

But in April last year, scientists proved that it was highly unlikely that HIV was spread by a contaminated polio vaccine.

It had been suggested that HIV was initially transmitted to humans in the late 1950s through the use of an oral polio vaccine.

The polio vaccine was given to at least one million people in the former Belgian Congo and what are now Rwanda and Burundi.

The site of the 28 vaccination projects correlate closely with the earliest cases of HIV infection.

In his book The River, journalist Edward Hooper alleged that the vaccine was grown in chimpanzee kidneys and became contaminated with the simian form of HIV known as SIV.

However, three independent studies published in the journal Nature cast serious doubts on the controversial theory.