At least 93 people are dead or missing after an Israeli air strike on the town of Beit Lahia in northern Gaza, the Hamas-run health ministry says, in an attack that the United States called "horrifying".

Rescuers said a five-storey residential building was hit, and videos on social media showed bodies covered in blankets on the floor.

The Israeli military said it was "aware of reports that civilians were harmed today [Tuesday] in the Beit Lahia area". It added that the details of the incident were being looked into.

The Israel Defense Forces (IDF) have been operating in northern Gaza during the past two weeks, particularly in the areas of Jabalia, Beit Lahia and Beit Hanoun.

The director of the nearby Kamal Adwan hospital in Jabalia, Hussam Abu Safia, told the AFP news agency that children were being treated at the hospital, which is struggling to treat patients due to a lack of staff and medicines.

"There is nothing left in the Kamal Adwan Hospital except first aid materials after the army arrested our medical team and workers," Abu Safia said.

The IDF raided the hospital last week, saying it was being used by Hamas fighters.

State Department spokesman Matthew Miller said the US was "deeply concerned by the loss of civilian life in this incident. This was a horrifying incident with a horrifying result".

He pointed to "reports of two dozen children killed" in the attack.

The "tragic cost to civilians" in the latest strike "is another reminder of why we need to see an end to this war", Miller said.

Israel says its operations in northern Gaza are designed to prevent Hamas from regrouping and accuses them of embedding among the civilian population, which Hamas denies.

In a statement on Tuesday, it said it killed 40 “terrorists” in Jabalia, and in central Gaza it said it “eliminated many terrorists" over the past 24 hours including some who "attempted to plant explosives near the troops".

The northern Gaza Strip faces a deepening humanitarian crisis, with hundreds of thousands of people living in desperate conditions.

UN human rights chief Volker Türk said on Friday that "the Israeli military is subjecting an entire population to bombing, siege and risk of starvation".

He also said it was unacceptable that Palestinian armed groups were reportedly operating among civilians, including inside shelters for the displaced, and putting them in harm’s way.

On Monday, Israel's parliament voted through legislation to ban the UN's Palestinian refugee agency, Unrwa, from operating in the country, sparking warnings the delivery of aid to Gaza could be severely impacted..

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.

More than 42,924 people have been killed in Gaza, according to the health ministry, which does not distinguish between civilians and fighters in its figures.

Israel is not allowing international journalists from media organisations, including the BBC, independent access to Gaza, making it hard to verify facts on the ground.