More than 100 people were killed in an Israeli strike on a residential building in the northern Gaza town of Beit Lahiya, China Media Group reported on Wednesday, as ceasefire talks are underway with Hamas signalling openness to discuss a new deal.

Medics said at least 20 children were among the dead.

"A number of victims are still under the rubble and on the roads, and ambulance and civil defense crews cannot reach them," the territory's health ministry said in a statement on Tuesday.

Intense battles between Israeli troops and Hamas fighters were raging in northern Gaza, part of which Israel has recently laid siege to in an attempt to eradicate remnants of the group, a witness told CGTN.

On Monday, the Palestinian Civil Emergency Service said around 100,000 people were trapped in Jabalia, Beit Lahiya and Beit Hanoun without medical or food supplies.

The area continues to be under siege and there are only a handful of journalists inside it, the witness said on Wednesday.

The health ministry said those wounded in the Beit Lahiya strike could not receive care as doctors had been forced to evacuate the nearby Kamal Adwan Hospital.

"Critical cases without intervention will succumb to their destiny and die," the ministry said in a statement.

Gaza's emergency service said its operations had come to a halt because of the three-week Israeli assault into northern Gaza. Israel says its campaign is to destroy Palestinian militant group Hamas, whose fighters had regrouped in the area in the year-long war.

'Horrifying'

Israel's main ally the United States said it was concerned by the high casualty toll in Beit Lahiya, with State Department spokesperson Matthew Miller calling it a "horrifying incident with a horrifying result."

U.S. officials have reached out to the Israeli government to ask what happened, Miller told reporters, adding he was aware of reports that many of the dead were children.

The UN Human Rights Office said it was "appalled" by one of the deadliest single attacks in nearly three months, calling for a prompt, transparent investigation into the circumstances.

Ceasefire talks

Talks led by the U.S., Egypt and Qatar to broker a ceasefire resumed on Sunday after multiple abortive attempts. Egypt's president proposed a two-day truce to exchange four Israeli hostages held by Hamas for Palestinian prisoners, followed by talks within 10 days on a permanent ceasefire.

Israeli Prime Minister Benjamin Netanyahu had said mediators would resume talks in coming days "in a continued attempt to advance a deal."

Israel has repeatedly said the war will go on until Hamas is eradicated while the Islamist movement has ruled out any end to fighting until Israeli forces leave Gaza.

Sami Abu Zuhri, a senior Hamas official, said in a televised speech that the movement is open to any agreements or ideas that would end the suffering of the people in Gaza and establish a permanent ceasefire.

He reiterated that any agreement should include the withdrawal of the Israeli army from all Gaza, the lifting of the blockade, and the provision of relief, support, and shelter for the Gaza population, as well as reconstruction and a serious prisoner swap deal.

Abu Zuhri's statement signalled no change to the faction's outstanding conditions. Israeli Prime Minister Benjamin Netanyahu says the war can only end when Hamas is eradicated.

(With input from Reuters, Xinhua)