The Israeli military and Palestinian militant group Hamas have agreed to three separate, zoned three-day pauses in fighting in the Gaza Strip to allow for the vaccination of some 640,000 children against polio, a senior WHO official said on Thursday.

The vaccination campaign is due to start on Sunday, said Rik Peeperkorn, the World Health Organization’s senior official for the region.

He said the campaign would start in central Gaza with a three-day pause in fighting, then move to southern Gaza, where there would be another three-day pause, followed by northern Gaza. Peeperkorn added that there was an agreement to extend the humanitarian pause in each zone to a fourth day if needed.

The WHO confirmed on Aug. 23 that at least one baby has been paralyzed by the type 2 polio virus, the first such case in the territory in 25 years.

The Israeli military’s humanitarian unit (COGAT) said on Wednesday that the vaccination campaign would be conducted in coordination with the Israeli military “as part of the routine humanitarian pauses that will allow the population to reach the medical centers where the vaccinations will be administered.”

(Reuters)