The World Health Organization has seen the first case of polio in Gaza in 25 years. On Thursday, the group said Israel and Hamas have agreed on a campaign to allow the vaccination of children throughout the enclave.

The WHO says the deal includes staggered pauses in the fighting in three zones from 6 AM until 3 PM for three days starting on Sunday. It is aiming to vaccinate 640,000 children, although it admits it may not have enough time to do so.

Rik Peeperkorn, a WHO representative in the West bank and Gaza, said: "I'm not going to say this is the ideal way forward. But this is a workable way forward. Not doing anything would be really bad. We have to stop this transmission in Gaza."

Polio is a highly contagious disease that mainly affects children under the age of five. Symptoms include fever, fatigue and pain in the limbs. Infections can lead to paralysis and, in some cases, death. Aid workers blame the resurgence on poor sanitation and the destruction of water supplies.

One resident said her 11-month-old son was diagnosed with polio and treated in the hospital, but he is paralyzed from the waist down.

She said, "I wish my child could have been treated better and will be able to walk again like other children."

The WHO says it hopes all parties will stick to the agreement, as it will need to follow up with a second dose of the vaccine four weeks after the first.