A polio vaccination campaign began in the central Gaza Strip on Sunday amid a temporary pause in hostilities.
The World Health Organization says Israel and Hamas have agreed on a humanitarian pause in areas where the vaccination rollout is underway.
Fighting stopped in central Gaza from Sunday morning till shortly after noon.
Many children, accompanied by adults, lined up and were vaccinated at a medical center in Nuseirat.
The vaccination campaign will move to southern Gaza and then northern Gaza, continuing for at least three days at each location.
The Qatar-based broadcaster Al Jazeera says two people, including a child, were killed by Israeli attacks in northern Gaza on Sunday.
Israeli forces announced on Sunday that they had found the bodies of six hostages, including a US national in a tunnel in Rafah in southern Gaza. They had been held by Hamas.
US President Joe Biden said, “Hamas leaders will pay for these crimes.” He added that the United States will keep working around the clock for a deal to secure the release of the remaining hostages.