The Israeli military mounted some of the fiercest attacks on Wednesday since Oct. 7 as it encircled southern Gaza's main city, Khan Younis.
Tel Aviv's closest ally the United States, in the meanwhile, again pressed to allow fuel and vital aid into the Palestinian enclave.
Israel said its forces, backed by warplanes, 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.
The Hamas-affiliated Al-Qassam Brigades said its fighters engaged in clashes with the military, which reported it had struck hundreds of targets in the enclave, including an alleged 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 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 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 Oct. 7 Hamas incursion. Thousands more are missing and feared buried under rubble.
Those figures were not immediately verified by the Gazan Health Ministry.
Israeli casualties, on the other hand, remain at around 1,200.
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 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.
Amid continued international concern over Gaza's plight, the United States, Israel's closest ally, reiterated 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 claimed 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 Tuesday accused Hamas of raping women and mutilating their bodies during its incursion of southern Israel.
In a statement on its 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.
Israel says several 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 Defense Minister Yoav Gallant on Tuesday condemned settler violence against Palestinians in the West Bank.