Nigeria is planning to roll out emergency polio vaccinations starting late August after reporting two new cases of the disease, UNICEF said Friday.

The new cases represent a major health setback for Nigeria, which was on track to be certified free of the virus next year, and highlights the difficulty of providing basic health services to people in the impoverished northeast region ravaged by Boko Haram insurgents.

The Nigerian government has "moved into emergency outbreak response mode", UNICEF spokesperson Priyanka Khanna said in a statement.

"Planning for a large scale campaign is in place," Khanna said, "The first campaign will start on 27 August, targeting 1.3 million . Subsequently two further rounds will be conducted, at two-to-three week intervals, reaching four-to-five million children."

Vaccination campaigns are also being planned in neighbouring countries with a focus on the Lake Chad region and northern Cameroon, Khanna added.

The campaign will start in Nigeria's northeast state of Borno, where the Nigerian government reported Thursday that two children had been paralysed by the disease.

Polio is a highly infectious viral disease that mainly affects young children and can result in permanent paralysis, according to WHO. There is no cure and it can be only prevented through immunisation.