ISLAMABAD An eight-month-old Pakistani girl has tested positive for polio in an area where militants campaigned against vaccination, a World Health Organization official said Thursday.

The girl, identified only as Tanzila, comes from Ali Gram village in the Swat Valley where militants had "beaten up" anti-polio vaccination teams, said Dr Khalid Nawaz, a WHO official supervising local health authorities.

Nawaz said the last confirmed case of the disease in Swat had been in 2003. Tanzila is infected with type 1 polio, the most dangerous and contagious strain, he said.

Threats to health workers and fighting between government security forces and militants have disrupted vaccinations in about half of the Swat Valley since September 2007, he said.

A Swat-based pro-Taliban cleric, Maulana Fazlullah, had reportedly opposed polio vaccination, saying it was a Western conspiracy to render Muslims infertile.

Last year, armed Fazlullah supporters took control of most of the scenic valley in Pakistans volatile northwest before the army moved in and forced them into the mountains.

Nawaz said authorities are planning to resume the vaccinations after a fragile peace deal was reached this year between militants and the government.

However, there have been sporadic attacks in recent weeks, and several girls schools have been burned down, amid signs that militants are reasserting themselves.

In the past year, Islamic militants have extended their influence across Pakistans northwestern frontier with Afghanistan, posing a growing security threat to both countries.

Polio has been eliminated in all but about a dozen countries following a global vaccination campaign, according to WHO. The disease remains endemic in Afghanistan, India, Nigeria and Pakistan.

Polio mostly strikes children under five and is spread when unvaccinated people come into contact with the feces of those with the virus, often through water. It usually attacks the nervous system, causing paralysis, muscular atrophy, deformation and sometimes death.

Nawaz said in 2007 there were 28 polio cases reported in Pakistan. So far this year there have been 17, but he remained confident that the spread of the disease could be stopped by years end.