Karachi polio killings: Vaccination workers shot

Four female Pakistani polio vaccination workers have been shot dead in the country's largest city Karachi, police say.

The victims were reportedly working with a UN-backed programme to eradicate polio, which is endemic in Pakistan.

No group has said it carried out the shootings, but the Taliban have issued threats against the polio drive and are active in parts of Karachi.

The attacks took place in three separate locations in the city.

Meanwhile, a teenage girl was wounded in an attack when gunmen opened fire on a team of female health workers on the outskirts of Peshawar in the north-west.

Key polio battleground
 
Pakistani health officials said the latest three-day nationwide anti-polio drive - during which an estimated 5.2 million polio drops were to be administered - had been suspended in Karachi due to the attacks.

There has been opposition to such immunisation drives in parts of Pakistan, particularly after a fake CIA hepatitis vaccination campaign helped to locate Osama Bin Laden in 2011.

Militants have kidnapped and killed foreign NGO workers in the past in an attempt to halt the immunisation drives which they say are part of efforts to spy on them.

Along with Afghanistan and Nigeria, Pakistan is one of only three countries where polio is still endemic.

Pakistan is considered the key battleground in the global fight against the disease, which attacks the nervous system and can cause permanent paralysis within hours of infection.

Nearly 200 children were paralysed in the country in 2011 - the worst figures in 15 years. 

Earlier this year, the Global Polio Eradication Initiative warned that tackling the disease had entered "emergency mode" after "explosive" outbreaks in countries previously free of polio.

The World Health Organization said polio was at a tipping point, with experts fearing it could "come back with a vengeance" after large outbreaks in Africa and Tajikistan and China's first recorded cases for more than a decade.

Declaring polio a national emergency, the Pakistani government is targeting 33m children for vaccination with some 88,000 health workers delivering vaccination drops.

In Karachi, Pakistan's biggest city of 18 million people, Health Minister Saghir Ahmed said on Tuesday that the government had told 24,000 polio workers it was suspending the anti-polio drive in Sindh province.

Poliomyelitis has existed as long as human society, but became a major public health issue in late Victorian times with major epidemics in Europe and the United States. The disease, which causes spinal and respiratory paralysis, can kill and remains incurable but vaccines have assisted in its almost total eradication today.