Israeli attacks across the Gaza Strip have killed dozens of Palestinians, including people seeking food at aid distribution hubs, as the already catastrophic humanitarian situation in the besieged enclave deteriorates by the day.

Medical sources told Al Jazeera on Sunday that at least 45 people were killed in Israeli strikes targeting multiple locations across Gaza, including 29 in Gaza City and the north of the territory.

Among them were at least five Palestinian aid seekers killed near food distribution centres run by the controversial Gaza Humanitarian Foundation (GHF) north of Rafah, according to local emergency workers quoted by an Al Jazeera correspondent on the ground.

Since the United States- and Israel-backed GHF took over limited aid deliveries in Gaza in late May amid a punishing Israeli blockade, Israeli soldiers have regularly shot at Palestinians near distribution centres, killing more than 580 people, and wounding more than 4,000, according to the Gaza Government Media Office.

A recent report by Israel’s Haaretz newspaper quoted unnamed Israeli soldiers as saying they had received orders to fire at crowds of unarmed aid seekers to disperse them.

“Heavy bombardment continues across the Gaza Strip, as we continue to get reports of a series of deadly incidents since dawn today,” said Al Jazeera’s Tareq Abu Azzoum, reporting from Deir el-Balah in central Gaza.

Azzoum said casualties included two children killed in an Israeli strike on a residential house in Gaza City’s Zeitoun neighbourhood. And multiple rockets also struck southern Khan Younis, where Israeli forces hit a makeshift tent in the coastal area of al-Mawasi, killing five people, he said.

“Witnesses report that booby-trapped explosives have been used to blow up entire residential neighbourhoods, as the Israeli military says it is concentrating operations in Khan Younis to defeat Hamas battalions there,” Azzoum added.

‘Most vulnerable are dying’

Meanwhile, the humanitarian crisis is worsening, with babies and toddlers dying due to a lack of nutrients.

Christy Black, an Australian nurse volunteering in Gaza City for four weeks now, says the hospital she’s based in is short of medical supplies, including formula for pregnant women who require nasogastric feeding. That leaves many without the nutrients needed to lactate – as well as baby formula, she said.

“Our most vulnerable are dying,” Black told Al Jazeera. “We’ve seen a couple of babies die over the last couple of days in Gaza City. It’s really desperate here.”

Malnourishment also makes it difficult to heal from wounds, she said, adding that there is a significant uptick in respiratory illnesses due to the number of bombs being dropped on Gaza.

“We’re seeing children going through the rubbish trying to find something to eat … Children who might be nine or 10 years old that look like two-year-olds,” she added.