Sarah Crowe, spokeswoman for UNICEF, said the vaccination program has been suspended everywhere in Pakistan until an investigation by the Pakistani government is completed.
“This is undoubtedly a tragic setback, but the campaign to eradicate polio will and must continue,” she said.
Some provincial governments in Pakistan continued to immunize children, independent of the U.N. drive.
Prevention efforts have managed to reduce the number of cases in Pakistan by around 70 percent this year compared to 2011, but the recent violence threatens to reverse that progress.