Intense shelling and gunfire rocked Rafah in southern Gaza on Thursday, after Israel declared it had seized a strategic corridor along the Palestinian territory's border with Egypt.
Israel launched its military incursion into Rafah in early May despite international objections over the safety of civilians sheltering in the city, reports AFP.
A strike that sparked a fire and killed dozens in a displacement camp at the weekend drew a wave of fresh condemnation.
Israel, which has repeatedly vowed to destroy Hamas after the Palestinian group Hamas attacked southern Israel on October 7, said on Wednesday its forces had taken over the 14-kilometre (8.5-mile) Philadelphi corridor along the Gaza-Egypt border, which it alleges was used for weapons smuggling.
Military spokesman Daniel Hagari said Israel had taken "operational control" of the narrow border strip, where he said troops had "discovered around 20 tunnels".
Egypt, a longtime mediator in the conflict, has rejected claims of smuggling tunnels running beneath the buffer zone.
"Israel is using these allegations to justify continuing the operation on the Palestinian city of Rafah and prolonging the war for political purposes," a high-level Egyptian source was quoted as saying by state-linked Al-Qahera News.
Egyptian officials have said a potential Israeli takeover of Philadelphi could violate the two countries' 1979 peace deal, though there has been no official comment from Cairo since the military's announcement.
- Civilians flee Rafah -
In Beijing, Egyptian President Abdel Fattah al-Sisi called for increased humanitarian assistance to Gaza, and reiterated his country's opposition to "any attempt at forcing Palestinians to flee their land".
His host, Chinese leader Xi Jinping, called for a "broad-based, authoritative and effective international peace conference" to address the war.
Hamas said later it had informed mediators that it would only agree a "comprehensive" truce agreement including a hostage-prisoner swap if Israel halts its "aggression".
On the ground in Gaza, witnesses reported fighting in central and western Rafah and bombardment in the east that killed at least five people near an aid warehouse.
AFP images from Al-Aqsa Martyrs Hospital in central Deir al-Balah showed children who appeared to be malnourished awaiting treatment.
The UN has warned of looming famine in Gaza. Israel said at the weekend that aid deliveries had been stepped up, including through its Kerem Shalom crossing with Gaza.
Witnesses said Israeli forces demolished buildings in east Rafah where the Israeli incursion began on May 7, initially focusing on the vital Rafah border crossing, a key entry point for aid.
On Thursday, Israel said its army had killed about 300 Palestinian Hamas in Rafah since launching its operation in the city.
A stream of civilians fled Rafah, taking their belongings on their shoulders, in cars or on donkey-drawn carts.
Before the Rafah offensive began, the United Nations said up to 1.4 million people were sheltering in the city. Since then, one million have fled the area, the UN agency for Palestinian refugees, UNRWA, has said.
Bd pratidin English/Lutful Hoque
