Image copyright AP Image caption Polio eradication teams have for the first time in two years been able to reach areas previously controlled by militants opposed to vaccination programmes

Polio cases in Pakistan have dropped by 70% this year as troops make territorial advances in the north against militants opposed to vaccination programmes, government officials have told the BBC.

They say that so far in 2015 there have been about 25 cases.

In October officials said that Pakistan had its highest number of cases for 15 years, mostly due to militant attacks.

At that time they said there were more than 200 cases across the country.

The number in October exceeded the 199 cases in 2001 but was short of the 558 cases in 1999.

Most polio infections are in the north-western tribal region where militants have targeted health teams.

They accuse doctors of being spies and say the vaccinations are part of a Western plot to sterilise Muslims.

'Army a great help'

Prime ministerial polio adviser Ayesha Raza said on Wednesday that while it had taken time to eradicate militancy in North Waziristan, the rewards from doing so were "already visible in the polio programme".

Ms Raza told the BBC that polio samples from high-incidence zones - which used to be positive for months on end - were now testing negative again.

The Federally Administered Tribal Areas (Fata) had only reported seven cases so far this year, she said, while Karachi had reported none.

"The army has been a great help in both these areas," Ms Raza said.

"With their help, and with the help of funding from the United Arab Emirates, we have been able to extend immunisation drives to high-risk areas.

Image copyright EPA Image caption Only one case of polio has been reported in Afghanistan in 2015

Image copyright EPA Image caption Only seven cases of polio have been recorded in Pakistan's Federally Administered Tribal Areas (Fata) so far this year, officials say

"We got access to populations in Waziristan after more than two years. We have also now penetrated some formerly no-go zones in Karachi."

Officials say that in recent months there has also been a clear decline in the number of attacks on polio teams. A number of men involved in such attacks have been arrested.

The BBC's M Ilyas Khan in Islamabad says that while Pakistan is celebrating the latest figures, the two other countries in the world where polio is endemic have done equally well if not better.

Nigeria has reported no new cases this year, and Afghanistan has only reported one.

Our correspondent says that a major chunk of the North Waziristan population who lived under a militant-imposed vaccination ban for several years have now been vaccinated several times over along with their children.