- Egypt's Sisi accuses Israel of restricting aid access to put pressure on Gaza
Israeli forces cut off southern Gaza's main hospitals in their assault, Palestinian officials said, and closed the main escape route for hundreds of thousands of residents and people who have sought refuge in the city.
Footage circulating among Palestinians showed black smoke pouring into the sky above the training centre, run by UNRWA, the UN relief organisation for the Palestinians. An UNRWA team trying to reach the centre was blocked, the organisation's director of Gaza affairs, Thomas White, said.
In response to questions about the shelling, the Israeli military said the wider area was a significant base of Hamas.
"Dismantling Hamas' military framework in western Khan Younis is the heart of the logic behind the operation," it said.
Several sources had earlier told Reuters that Israel and the Hamas group that runs Gaza had made some progress in proxy talks on a 30-day ceasefire, during which Israeli hostages and Palestinian prisoners would be freed and more aid would enter the enclave.
But that prospect appeared distant on Wednesday.
In their biggest operation in a month, Israeli tanks have pushed through Khan Younis, where many Palestinians are sheltering after leaving the north - the early focus of the war.
Their main target appears to be the area around Khan Younis' long-standing refugee camp, which includes the Nasser and Al-Amal hospitals and also the training centre run by UNRWA.
"Attack on Khan Younis Training Centre this afternoon - two tank rounds hit building that shelters 800 people - reports now 9 dead and 75 injured" UNRWA's White said on X.
Residents reported fierce gunbattles in the area, where the military said it had killed "numerous" squads of gunmen "with sniper, tank and aerial fire".
Gaza health ministry spokesman Ashraf Al-Qidra said in a statement: "The occupation is isolating hospitals in Khan Younis and carrying out massacres in the western area of the city."
The Palestinian Red Cross Society, which runs the Al-Amal hospital, said troops had blockaded its staff inside and imposed a curfew in the area, including its local headquarters, where three displaced individuals had been killed.
Israel says Hamas fighters operate in and around hospitals, which hospital staff and Hamas deny.
Martin Griffiths, UN coordinator of emergency relief, said on Tuesday that 24 people had been killed in strikes on an aid warehouse, UN centre and humanitarian zone in the Khan Younis area, and that an aid distribution centre had come under heavy bombardment.
The Israeli military had earlier ordered the evacuation of the area, which the UN humanitarian office said held half a million people, four-fifths of them displaced by fighting in other parts of the coastal strip.
However, Israeli tanks advancing eastward down al-Bahar road towards Nasser hospital blocked the escape route from the city towards the Mediterranean coastal highway.
The highway leads towards Rafah on the Egyptian border - already crammed with more than half the enclave's 2.3 million people. Some resorted to dirt roads to try to escape, residents and reporters leaving the area said.
Palestinian health officials said at least 25,700 Gazans had been killed in the war, including 210 in the previous 24 hours, with thousands more feared lost under rubble.
Israel says it has killed around 9,000 militants, a figure that Hamas dismisses as an attempt to "portray a fake victory".
Qatar, the US and Egypt have for weeks shuttled between Israel and Hamas trying to broker terms for a break in fighting, which would also allow in more food and medical supplies.
More than 130 hostages are still being held in Gaza, according to Israeli tallies.
In November, each side blamed the other for the collapse of a seven-day truce in which Hamas had freed women, children and foreign hostages in exchange for daily releases of Palestinians from Israeli prisons.
But the two sides remain at odds over how to permanently end the war, which Hamas insists must be decided as part of any ceasefire agreement, sources told Reuters.
Commenting on the report of ceasefire negotiations shortly after the two-far right partners in Prime Minister Benjamin Netanyahu's coalition expressed strong concerns, government spokesperson Ilana Stein issued a flat denial.
"Israel will not give up on the destruction of Hamas, the return of all the hostages, and there will be no security threat from Gaza towards Israel," she said in a briefing.
"There will be no ceasefire. In the past there were pauses for humanitarian purposes. That agreement was breached by Hamas."
The White House reiterated its insistence that Gaza's future government could not include Hamas leaders, prompting Hamas to say it would not let the US or anyone else "enforce a mandate on our free people".
White House spokesperson John Kirby said the US would support a pause in combat to free hostages and let aid in, but gave no timeframe and said he would not call the discussions "negotiations". But he said US Middle East envoy Brett McGurk was in Cairo and due to hold "active" discussions.
Egyptian President Abdel Fattah al-Sisi accused Israel of holding up aid deliveries from the Rafah border crossing into Gaza as "a form of pressure on the Gaza Strip and its people over the conflict and the release of hostages".
