WATCH: Louise Greenwood reports on the latest from Gaza and Israel

Israel pounded Hamas-ruled Gaza with more air and ground attacks on Sunday in an escalating military campaign as the UN warned civil order was "starting to break down" in the besieged Palestinian territory.

Israeli Prime Minister Benjamin Netanyahu steeled the nation for a "long and difficult war" ahead in a late-night televised address as the Red Cross voiced shock at the "intolerable level of human suffering" inside Gaza.

More than three weeks after the October 7 attacks, Israel has intensified the escalation despite UN calls for a humanitarian ceasefire, outrage across the Muslim world and desperate pleas from families of the 230 hostages to "bring them home."

The ground operations have heightened fears Israel's other enemies - the Iran-allied "axis of resistance" forces in Lebanon as well as Syria, Iraq and Yemen - could join the conflict.

Stage two of the conflict

After weeks of heavy bombardment of Gaza, which the Hamas-ruled health ministry said has claimed over 8,000 lives, the army said "stage two" of the conflict started with ground incursions since Friday.

Israel's military said early on Sunday it had struck another 450 Hamas targets over 24 hours and that it was increasing the number of ground forces in Gaza. 

"As part of the expansion of ground activities, combined combat forces struck terrorist cells that attempted to attack the forces," it added, reporting that two Israeli soldiers were wounded, one severely by a mortar shell.

Israel unleashed its massive retaliation on October 7 after Hamas gunmen stormed across the border, killing 1,400 people, mostly civilians, according to Israeli officials.

Netanyahu said on Saturday that "this is the second stage of the war whose goals are clear: Destroying the military and leadership capabilities of Hamas and bringing the hostages back home."

He vowed to "eradicate" Hamas "for the sake of our existence".

Panic and fear have surged inside Gaza, where over one million people are displaced, and where communications went dark for days after Israel cut internet lines, although connectivity gradually returned on Sunday.

The UN agency for Palestinian refugees said "thousands of people broke into several UNRWA warehouses and distribution centers in the middle and southern areas of the Gaza Strip, taking wheat flour and other basic survival items like hygiene supplies.

"This is a worrying sign that civil order is starting to break down after three weeks of war and a tight siege on Gaza. People are scared, frustrated and desperate." 

Hamas authorities reported on Sunday that a "large number" of people were killed overnight in strikes on two refugee camps in northern Gaza.

Defence Minister Yoav Gallant has said Israel was attacking "above the ground and below", alluding to Hamas' sprawling tunnel network.

Israeli fighter jets again dropped leaflets over Gaza City on Saturday, warning residents that the northern area was now a "battlefield" and they should "evacuate immediately".

While Israel has mourned its dead, there has also been intense sympathy with the families whose loved ones are still inside Gaza and at heightened risk as the conflict intensifies.

Hamas has released four of them but this week also claimed that "almost 50" had been killed by air strikes, a claim that was impossible to verify.

READ MORE

Lagarde's interest rate freeze explained

WHO demands fuel access for Gaza

Gaza getting 'crumbs of aid'

Hamas's armed wing the Ezzedine al-Qassam Brigades said it was ready to release the hostages if Israel freed all the Palestinian prisoners it was holding.

Hamas's leader in Gaza, Yahya Sinwar, said the group stood ready to make an "immediate" exchange.

Netanyahu met representatives of hostage relatives on Saturday. He made no commitment to any exchange deal but assured the families Israel would "exhaust every option to bring them home."

Israel's ally the U.S. has sternly warned Israel's enemies not to get involved, a warning underscored by two aircraft carrier battle groups it has moved to the eastern Mediterranean off Israel and Lebanon.

Iran's President Ebrahim Raisi warned Sunday in a message on X, formerly Twitter, that Israel's "crimes have crossed the red lines, which may force everyone to take action." 

Israel would allow a dramatic increase in aid to Gaza in the coming days, Colonel Elad Goren of Cogat, the Israeli Defence Ministry agency that co-ordinates with the Palestinians, said on Sunday.

The Palestinian Red Crescent said it has received warnings from Israeli authorities to immediately evacuate al-Quds hospital in the Gaza Strip.

Subscribe to Storyboard: A weekly newsletter bringing you the best of CGTN every Friday