The long-awaited final phase of a UN-supported polio vaccine campaign began on Saturday in bombarded, besieged northern Gaza even as reports emerged that one vaccination centre had been hit during a humanitarian pause, according to UN agencies on the ground.

Hours after the campaign rolled out, reports indicated that a healthcare centre in the north had been hit, injuring six people, including four children, in a location where a humanitarian pause had been in place, according to the World Health Organization (WHO) chief.

“We have received an extremely concerning report that the Sheikh Radwan primary healthcare centre in northern Gaza was struck today while parents were bringing their children to the lifesaving polio vaccination in an area where a humanitarian pause was agreed to allow vaccination to proceed, ” said Tedros Adhanom Ghebreyesus in a social media post.

He said a WHO team was at the site just before.

“This attack, during humanitarian pause, jeopardises the sanctity of health protection for children and may deter parents from bringing their children for vaccination,” he said. “These vital humanitarian-area-specific pauses must be absolutely respected.”