A ship carrying aid to people in Gaza is expected to reach the shoreline of the coastal strip on Thursday morning, about 48 hours after it left Cyprus, and shortly after the EU foreign policy chief said starvation was being used as a weapon of war.

Separately, a new land route was used to deliver food to northern Gaza for the first time in three weeks, the UN said. In southern Gaza, an aid warehouse run by the UN agency for Palestinian refugees was bombed, according to the Hamas-run health ministry, which said four people were killed.

More than halfway through its 240-mile voyage, it was still unclear where the aid ship would dock and how supplies would be distributed. It is towing a barge carrying 200 tonnes of water, food and vital medicines. Those behind the aid mission – Cyprus, the EU, the United Arab Emirates, the US and UK – were expected to issue a joint statement on Wednesday evening on their next steps.

Hamas said the delivery of aid by sea was inadequate to meet the needs of people who are in desperate need of food, water and medical supplies.

“The ship’s cargo does not exceed that of one or two trucks, and it will take days to arrive,” Salama Marouf, the head of the Hamas government media office, said in a statement. “It is still unknown where it will dock and how it will reach the shores of Gaza. Moreover, it will be subject to inspection by the occupying army.”

The Spanish-flagged vessel Open Arms is the first to ply a newly opened humanitarian sea corridor established between the Cyprus port of Larnaca and Gaza.

Josep Borrell, the UN’s foreign policy chief, said the lack of aid reaching Gaza was a man-made disaster. “We are now facing a population fighting for their own survival,” he told the UN security council in New York on Tuesday. “Humanitarian assistance needs to get into Gaza, and the European Union is working as much as we can in order to make it possible.

“[The humanitarian crisis is] man-made, and when we look for alternative ways of providing support by sea, by air, we have to remind [ourselves] that we have to do it because the natural way of providing support through roads is being … artificially closed.

“Starvation is being used as a war arm, and when we condemned this happening in Ukraine, we have to use the same words for what is happening in Gaza.”

The most efficient way to get aid to Gaza is by road, but aid agencies say Israeli restrictions mean a fraction of what is needed is getting in. Attention has instead shifted towards alternative routes, including sea and air drops.

On Tuesday, enough food for 25,000 people was delivered to Gaza City via a UN World Food Programme (WFP) convoy of trucks using an Israeli military road running along Gaza’s border fence.

The delivery proved that “moving food by road is possible”, said WFP spokesperson Shaza Moghraby. “We are hoping to scale up. We need access to be regular and consistent – especially with people in northern Gaza on the brink of famine. We need entry points directly to the north.”

The Israeli military said six WFP lorries crossed via a new gate in the Gaza border fence. It was “part of a pilot to prevent Hamas from taking over the aid”, it added.

Israel insists there are no limits to the amount of aid that can be delivered into and across Gaza, and blames UN agencies for failing to distribute supplies. “We are constantly trying to find creative ways to maintain the flow of humanitarian supplies into Gaza,” military spokesperson Lt Col Peter Lerner wrote on X.

The UN says “ongoing fighting and Israeli bombardment, as well as insecurity, frequent border closures and access constraints” have impeded safe and efficient aid operations.

Juliette Touma, spokesperson for Unwra, the UN agency for Palestinian refugees, said one of its aid warehouses in southern Gaza had been hit on Wednesday, wounding scores of people.

“We can confirm that an Unwra warehouse/distribution centre in Rafah has been hit,” she said. “We do not yet have more information on what exactly happened nor the number of Unrwa staff impacted. Unrwa uses this facility to distribute much needed food and other lifesaving items to displaced people in southern Gaza.”

According to the Hamas-run health ministry, four people were killed in the bombing.

Last month, more than 100 people were killed trying to reach an aid convoy south-west of Gaza City, according to Gaza’s health ministry. Palestinians said most were shot by Israeli troops overseeing the delivery, but the Israeli military said most were killed in a stampede or run over.

Last week, the WFP attempted to resume deliveries to the north, but said a convoy was “turned back” by Israeli forces before being looted by a crowd.

Western and Arab countries have carried out more than 30 airdrops since the start of the war, mostly over northern Gaza. However, they are considered ineffective and costly, and last week five people were reportedly killed north of Gaza City due to the malfunction of a parachute on one airdropped package.

The UN says at least 576,000 Palestinians in Gaza – a quarter of the population – are one step away from famine.

Gaza’s health ministry says 27 people, including 23 children, have died from malnutrition and dehydration at hospitals in the past two weeks.