Three female polio vaccination health workers shot dead in eastern Afghanistan

Gunmen killed three female polio vaccination workers in the eastern Afghan city of Jalalabad on Tuesday, officials said, adding that a blast had also rocked the provincial health department headquarters but left no casualties.

Ghulam Dastagir Nazari, head of the immunisation programme at Afghanistan's Health Ministry, told Reuters the explosion took place at the entrance to the health department for the province of Nangarhar late on Tuesday morning.

Around the same time unknown gunmen shot vaccination workers at two separate locations in Jalalabad, killing two volunteers and one supervisor in the polio immunisation programme, all of them women, he said.

There was no immediate claim of responsibility. Zabihullah Mujahid, spokesman for the main insurgent movement, the Taliban, said they had no role in the attacks.

A wave of assassinations has hit urban centres since peace talks began between the Taliban and the Afghan government last year in Doha, many of them targeting professional women as well as government employees, media and civil society members.

Afghanistan and Pakistan are the only countries in the world where polio remains endemic. Afghanistan kicked off a polio vaccination programme this week, backed by the UN chidren's agency UNICEF.

Rabia, a 20-year old vaccinator in Jalalabad who asked that only her first name be published for security reasons, told Reuters she was in a state of shock.

"Today I am very worried, I do not think my family will allow me to work as a polio vaccinator anymore, because they are afraid that one day I will be killed too," she said.

US Charge D'Affaires Ross Wilson said: "Attacking vaccinators is as heartless as it is inexplicable."

"This campaign is an important step to protect Afghan children from facing an infectious disease that can cause debilitating paralysis," he said on Twitter.

Three female journalists were killed in Jalalabad this month, an attack claimed by Islamic State. The government blames most targeted killings on the Taliban, who deny carrying out assassinations.

Militant groups including the Taliban have targeted health workers in the past. The UN mission to Afghanistan warned last year that health workers were increasingly at risk after a series of attacks. One attack on a Kabul maternity ward in May killed twenty-four people.