Gunmen suspected of belonging to a radical Islamic sect have shot and killed at least nine women taking part in a polio vaccination drive in northern Nigeria, Belfast Telegraph said.

The attack highlights the religious tensions surrounding the inoculation of children in one of the few nations where the disease still remains endemic.

The attack shocked residents of Kano, the largest city in Nigeria's predominantly Muslim north, where women often go from house to house to carry out the vaccination drives as Muslim families feel more comfortable allowing them inside their homes than men.

It also signalled a new wave of anger targeting immunisation drives in Nigeria, where clerics once claimed the vaccines were part of a Western plot to sterilise young girls.

The first attack happened in Kano's Hotoro Hayi neighbourhood and saw gunmen arrive by three-wheel taxis and open fire. At least eight female vaccinators died in that attack, witnesses said. The second attack, in the Unguwa Uku neighbourhood, saw another four people killed.

While police said they had no immediate suspects for the attacks, witnesses said they believed that Boko Haram had been behind the shootings. Boko Haram, whose name means "Western education is sacrilege" in the Hausa language of the north, has been behind a series of violent attacks across northern Nigeria as part of its fight against the country's weak central government.

In December, militants in Pakistan killed at least nine workers on a polio vaccine drive. Militants there have accused health workers of acting as spies for the US, alleging the vaccine is intended to make Muslim children sterile.