The United Nations and local health authorities have extended a campaign to vaccinate children in the southern Gaza Strip against polio by an extra day. 

Gaza's health ministry reported the first case of polio in 25 years last month, amid the Israel-Hamas war in the Palestinian territory.

The campaign aims to vaccinate 640,000 children in Gaza, 200,000 of them in the south, according to UNRWA, the UN agency responsible for Palestinian refugees.

"I live in a tent next to a sewage pond with significant disease and epidemic issues, and mosquitoes and worms have infected us," said 37-year-old Amani Ashur, who brought his one-year-old son Abdul Rahman to be vaccinated.

He said the boy had fallen ill from diseases spreading through makeshift shelters in the Al-Amal neighbourhood of Khan Younis.

"The war, lack of cleanliness, and living in tents and streets, along with the widespread sewage issues, have all contributed to the spread of disease," Safaa al-Balbisi, 34, said about her two-year-old son Yahya. 

The first phase of the vaccination campaign in the middle areas of Gaza started on September 1.

The second phase in the southern Gaza Strip began on Thursday and was extended on Sunday, before it moves to the north on Monday for the third phase.

UN officials said they were making progress, having reached more than half of the children needing the oral drops in the first two stages of the campaign.

Follow-up vaccinations will take place in a month's time.

Limited pauses in the fighting to allow the vaccinations to go ahead have been agreed to by Israel, Palestinian groups and the UN's World Health Organization (WHO).

An Israeli air strike on a house in Jabalia in northern Gaza killed the deputy director of the Gaza Civil Emergency Service on Sunday, health officials said.

Four members of Mohammad Morsi's family were also killed, the officials said.

There was no immediate Israeli comment on Mr Morsi's death.

Residents said Israeli forces had also blown up several houses in the Zeitoun suburb of Gaza City, five kilometres from Jabalia.

Medical teams said they were unable to answer desperate calls by some of the residents who had reported being trapped inside their houses, some wounded.

"We hear constant bombing in Zeitoun, we know they are blowing up houses there, we don't sleep because of the sound of explosions, the roaring of tanks sound close and the drones don't stop circling," said a resident who lives about 1km away.

The latest bloodshed in the decades-old Israeli-Palestinian conflict was triggered on October 7 when the Hamas militant group attacked Israel, killing 1,200 people and taking about 250 hostages, according to Israeli tallies.

Israel's subsequent assault on Gaza has killed more than 40,900 Palestinians, according to the local health ministry, while also displacing nearly the entire population of 2.3 million, causing a hunger crisis and leading to genocide allegations at the World Court, which Israel denies.

AFP/Reuters