A government official on Monday said authorities have launched a new polio vaccination drive, aiming to reach 38.7 million children under the age of five. Pakistan is one of few countries where polio is still endemic, along with Afghanistan and Nigeria.

Dr Rana Mohammad Safdar, the national coordinator for polio eradication, says that some 260,000 polio workers will take part in the campaign, which started on Monday.

He says authorities hope a similar campaign will soon be launched in the tribal regions.

Polio workers and their police escorts often come under attack by militants. The attacks stepped up after it was revealed that a CIA fake hepatitis vaccination campaign was used as a ruse to find Osama bin Laden in Pakistan. The al-Qaida leader was killed by US commandos in 2011.