In Nangarhar province of Afghanistan, public health ministry has reported three new polio cases, an official said.
Ministry spokesman Wahidullah Mayar said the three new polio cases were identified in Achin and Shirzad districts, Khaama Press reported.
Although polio has been eradicated all across the globe, the disease remains rife in Afghanistan and Pakistan.
Currently Afghan health workers are positioned at every border crossings in an attempt to monitor all children who are at risk of contracting the disease.
However, many people do not cross the border at formal customs posts, choosing instead to use tracks across the mountains and deserts.
This makes it increasingly difficult for health workers to identify any potential health risks.