Dozens of people are reported to have been killed in overnight Israeli air strikes in northern Gaza.

Paramedics and Hamas-affiliated media said at least 66 were killed, including women and children, when several houses sheltering displaced people were hit near Kamal Adwan hospital in the town of Beit Lahia. One unverified video showed more than 20 bodies lined up in a street.

Another 22 people were killed in a strike on a house in the northern Sheikh Radwan neighbourhood of Gaza City, according to the Hamas-run Civil Defence agency.

The Israeli military said it had struck Hamas infrastructure in Beit Lahia and that it had taken steps to mitigate harm to civilians. It did not comment on the Gaza City incident.

Deadly Israeli strikes were also reported elsewhere in Gaza on Thursday.

Nasser hospital in the southern city of Khan Younis said it had received the bodies of 24 people killed in Israeli military action there and in nearby Rafah.

The Israeli military has recently intensified its ground offensive in parts of northern Gaza, saying it is stopping Hamas from regrouping there.

The UN has said Beit Lahia, as well as the nearby towns of Beit Hanoun and Jabalia, are under siege and that virtually no humanitarian aid has been delivered since early October.

Photographs from the scene of the air strike in Beit Lahia on Thursday morning showed piles of rubble and twisted metal, about 55m (185ft) away from Kamal Adwan hospital.

Its director, Dr Hussam Abu Safiya, said there were “dozens of dead or missing”.

“Bodies arrive at the hospital in pieces,” he told AFP news agency. “But there are no ambulances, the health system is on its knees in northern Gaza.”

Dr Abu Safiya said the hospital was only able to provide first aid to most casualties brought there because Israeli forces were not allowing in enough medical supplies.

The Israeli military said in a statement that it had “struck Hamas terrorist infrastructure in the area of Beit Lahia” overnight and that members of Hamas had been operating there, including a number who took part in the 7 October 2023 attack on Israel that triggered the Gaza war.

“Prior to the strikes, numerous steps were taken to mitigate the risk to civilians, including the use of aerial surveillance, warning the population in the area to evacuate the active combat zone, and additional intelligence information,” it added. “The incident is under review.”

Israel’s ground offensive in northern Gaza has displaced up to 130,000 people over the past five weeks.

The UN says 75,000 people remain under siege with dwindling supplies of water and food in Beit Lahia, Jabalia and Beit Hanoun.

Last week, a report by Human Rights Watch said Israel had committed war crimes and crimes against humanity by deliberately causing the mass displacement of Palestinians in Gaza. Israel said the report was “completely false and detached from reality”.

About 1.9 million people – 90% of Gaza’s population – have fled their homes over the past year, and 79% of the territory is under Israeli-issued evacuation orders, according to the UN.

Israel launched a campaign to destroy Hamas in response to the group’s unprecedented attack on southern Israel on 7 October 2023, in which about 1,200 people were killed and 251 others were taken hostage.

Nearly 44,000 people have been killed and more than 104,000 injured in Gaza since then, according to the territory’s Hamas-run health ministry.

On Wednesday, the US blocked a Gaza ceasefire draft resolution at the UN Security Council – the fourth time it has used its veto power during the conflict to shield its ally, Israel.

Fourteen of the 15 council members voted in favour of the draft, which demanded that the war in Gaza “must end immediately, unconditionally and permanently and all remaining hostages must be immediately and unconditionally released”.

Deputy US ambassador to the UN, Robert Wood, said the document “abandoned” the necessity for there to be “a linkage between a ceasefire and the release of hostages”.

Wood said the proposed resolution would have sent a “dangerous message” to Hamas that “there’s no need to come back to the negotiating table”.

In a separate development, US mediator Amos Hochstein has arrived in Israel from Lebanon.

He has said that he sees a “real opportunity” to end the conflict in Lebanon after the Lebanese government and Hezbollah largely agreed to a US ceasefire proposal.