By Bassam Masoud and IbraheemAbu Mustafa
GAZA (Reuters) -Israel's military bombarded southern Gaza's main city in what it said was the heaviest fighting since it began a ground invasion to eliminate Hamas five weeks ago, while the United States again pressed Israel to allow fuel and vital aid into the Palestinian enclave.
Israel said its forces, backed by war planes, were engaged in fierce battles in Gaza on Wednesday, a day after the military reached the heart of Khan Younis and also surrounded the city.
Hamas' armed wing, the al Qassam Brigades, said its fighters engaged in clashes with the military, which reported it had struck hundreds of targets in the enclave, including a militant cell near a school in the north.
The surge in combat comes after a truce between Israel and Hamas collapsed last week.
Hamas' armed wing said it killed or wounded eight Israeli troops and destroyed 24 military vehicles on Tuesday. An Israeli military website listed two troop deaths for Tuesday and 83 since the ground operation began.
Gaza health officials said many civilians were killed in an Israeli strike on houses in Deir al-Balah, north of Khan Younis. Dr Eyad Al-Jabri, head of the Shuhada Al-Aqsa Hospital there, told Reuters at least 45 people were killed. Reuters could not reach the area nor confirm the toll.
Hamas' media office said on Tuesday at least 16,248 people including 7,112 children and 4,885 women had been killed in Gaza by Israel's military since the conflict erupted on Oct. 7. Thousands more are missing and feared buried under rubble.
Those figures were not immediately verified by the Gaza health ministry.
Israel unleashed its campaign in response to an attack by Hamas fighters who rampaged through Israeli towns, killing 1,200 people and seizing 240 hostages, according to Israel's tally.
Israeli police are investigating alleged sexual crimes during that killing spree and the justice ministry has said victims were tortured, abused, raped, burned alive, and dismembered.
U.S. PRESSURE ON ISRAEL
Since the truce collapsed, Israel has been posting an online map to tell Gazans which parts of the enclave to evacuate to avoid attacks. Khan Younis' eastern quarter was marked on Monday, and many of its hundreds of thousands of residents took flight on foot.
Gazans say there is no safe place, with remaining towns and shelters already overwhelmed, and Israel continuing to bomb the areas where it is telling people to go.
At Khan Younis' main Nasser Hospital, the wounded arrived by ambulance, car, flatbed truck and donkey cart after what survivors described as a strike on a school being used as a shelter for the displaced.
Inside a ward, almost every inch of blood-splattered floor space was taken up by the wounded including small children, with medics hurrying from patient to patient while relatives wailed.
Two girls were being treated, still covered in dust from the collapse of the house that had buried their family.
"My parents are under the rubble," sobbed one child. "I want my mum, I want my mum, I want my family."
Amid continued international concern over Gaza's plight, the United States, Israel's closest ally, reiterated on Tuesday that Israel needed to do more to allow fuel and other aid into Gaza and reduce harm to civilians. Despite the mounting death toll, it said Israel was now showing some receptiveness to the calls.
"The level of assistance that's getting in is not sufficient," U.S. State Department spokesperson Matthew Miller said at a press briefing. "It needs to go up, and we've made that clear to the government of Israel."
U.S. President Joe Biden said on Tuesday that Hamas had repeatedly raped women and mutilated their bodies during its assault on southern Israel, citing survivors and witnesses.
"It is appalling," he told a political fundraiser in Boston.
In a statement on Telegram channel, Hamas denounced Biden's accusations as false and said he was joining Israel's effort to cover up war crimes committed with U.S. support.
Israeli Prime Minister Benjamin Netanyahu cited the claims of rape and other abuse in a meeting with families of returned hostages that some participants described as angry because of frustration over the government's handling of the situation.
"I heard stories that broke my heart...I heard and you also heard, about sexual assault and cases of brutal rape unlike anything," Netanyahu said at a press conference.
Israel says a number of women and children remain in Hamas hands. During the pause in fighting, Hamas returned more than 100 hostages while 138 captives remain.
Biden blamed Iran-backed Hamas for the collapse of the truce last week, saying the militant group's "refusal to release the remaining young women is what broke this deal".
Israel and Hamas have accused each other of wrecking negotiations.
Hamas official Osama Hamdan said there would be no more hostages released until Israel's aggression stopped.
Separately, the U.S. imposed visa bans on people involved in violence in the Israeli-occupied West Bank after appeals for Israel to do more to prevent attacks on Palestinians by Jewish settlers. Two Palestinian teenagers were killed by Israeli troops in Tubas, West Bank, the official Palestinian WAFA news agency reported on Wednesday.
Israeli Defence Minister Yoav Gallant on Tuesday condemned settler violence against Palestinians in the West Bank.
(Reporting by Reuters bureax; Writing by Cynthia Osterman and Stephen Coates; Editing by Miral Fahmy)