The Israeli military denied on Monday that it had hit a clinic in the northern Gaza Strip where health workers were carrying out polio vaccinations.

On Saturday, the Gaza health ministry said Israeli fire had hit the Sheikh Radwan clinic as parents brought their children in to be vaccinated. It said four children had been wounded in the explosion, which took place during an agreed humanitarian pause to allow the campaign to go ahead.

The military said it was aware of the reports but said an initial review showed its forces had not carried out any strikes when the incident took place.

"Contrary to the claims, an initial review determined that the IDF did not strike in the area at the specified time," it said in a statement.

The head of the World Health Organization, Tedros Adhanom Ghebreyesus, said the incident had taken place just after a WHO team was at the clinic and that it had endangered a vital health protection campaign.

"These vital humanitarian-area-specific pauses must be absolutely respected. Ceasefire!" he said in a statement on the social media platform X on Saturday.

The Israeli military accused the Palestinian militant group Hamas of deliberately operating out of civilian areas to use people as human shields, a charge that Hamas denies.

With access to the area cut off and communications patchy, outside verification of the assertions of either side has become increasingly difficult.