The Taliban has suspended polio vaccination campaigns across Afghanistan, the United Nations announced Monday. News of the suspension was relayed to U.N. agencies right before the September immunization campaign was due to start.

The Taliban have suspended polio vaccination campaigns in Afghanistan, the U.N. said Monday. It’s a devastating setback for polio eradication, since the virus is one of the world’s most infectious and any unvaccinated groups of children where the virus is spreading could undo years of progress.

More than 560,000 children aged below 10 in Gaza have received the first of two doses of the polio vaccine, the World Health Organization (WHO) said on Friday, after Israel’s destruction of water and sanitation systems led to a resurgence of the deadly disease in the besieged strip.

On Monday, the AP news agency reported suspending the polio vaccination campaign in Afghanistan. Official reasons were not provided, but the opposition claims it is about limiting women's participation in vaccination efforts.