London, Feb 8 (IANS) Nine women polio vaccinators have been killed in two incidents of shooting at health centres in Nigeria, BBC reported Friday.
In the first attack in Kano, the vaccinators were shot by gunmen on a motor tricycle.
Gunmen later targeted a clinic in Hotoro outside Kano as the vaccinators prepared to start work.
BBC said some Nigerian Muslim leaders have opposed polio vaccinations, claiming these could cause infertility.
An Islamic cleric has said new cases of polio were caused by contaminated medicine.
According to the Global Polio Eradication Initiative, there were 121 cases of polio in Nigeria last year.
Experts believe the attacks may have been committed by militant Islamist group Boko Haram. The outfit has not made any comment.
The group has been blamed for the deaths of around 1,400 people in Nigeria since 2010.