Israel bombarded Gaza with more air strikes on Monday as its soldiers fought Hamas militants on the ground in raids within the besieged Palestinian enclave.
In signs that the conflict was spreading, Israeli aircraft also struck southern Lebanon overnight and Israeli troops fought Palestinians in the occupied West Bank, residents said.
The United Nations said desperate civilians were running out of food, water, and places to shelter from the unrelenting aerial pounding that has flattened swathes of Hamas-ruled Gaza.
Some aid was trickling over one border crossing into Gaza — but only a fraction of the amount needed.
Gaza authorities say at least 4,600 people have been killed in a two-week Israeli bombardment. That was triggered by on Israeli communities by Hamas militants who killed 1,400 people and took more than 200 hostage.
The significant escalation is the latest in a long-standing conflict between Hamas and Israel.
Hamas is a Palestinian military and political group, gaining power in the Gaza Strip since winning legislative elections there in 2006.
Hamas' stated aim is to establish a Palestinian state, while refusing to recognise Israel’s right to exist.
A damaged neighborhood in Gaza City pictured on Monday following Israeli airstrikes. Source: AAP, AP / Abed Khaled
Some countries list only its military wing as a terrorist group.
The UN though did not condemn Hamas in its entirety as a terrorist organisation, due to insufficient support from member states to do so during a 2018 vote.
Overnight clashes
Both Israel and Hamas reported overnight clashes in Gaza.
Israel on Monday said ground forces mounted limited raids to fight Palestinian gunmen and that air strikes were being focussed on sites where Hamas was assembling to attack any wider Israeli invasion.
"During the night there were raids by tank and infantry forces. These raids are raids that kill squads of terrorists who are preparing for our next stage in the war. These are raids that go deep," chief military spokesperson Rear Admiral Daniel Hagari said in a briefing.
People conduct a search and rescue operation for Palestinians stuck under the debris of a destroyed building after the Israeli airstrike in Rafah, Gaza on Sunday. Source: Getty / Anadolu
Hamas' armed wing, the Izz el-Deen al-Qassam Brigades, said its fighters engaged with an Israeli force that infiltrated Gaza and they destroyed some Israeli military equipment.
The group said the infiltration by what it described as an armoured force took place east of Khan Younis in southern Gaza.
"Fighters engaged with the infiltrating force, destroying two bulldozers and a tank and forced the force to withdraw, before they returned safely to base," a statement said. There was no Israeli comment about the destruction of equipment.
The Al-Qassam Brigades also on Monday they were firing missiles on the south Israeli towns of Ashkelon and Mavki'im. Warning sirens blared out on the Israeli side.
Earlier on Monday, the Israeli military said that in the past 24 hours it had struck more than 320 targets in Gaza, including a tunnel housing Hamas fighters, dozens of command and lookout posts, and mortar and anti-tank missile launcher positions.
Israel has been massing troops along the Gaza border. Source: AAP, EPA / Abir Sultan
Asked by Israeli Army Radio if Washington was pressuring Israel to hold off, Israel's deputy ambassador to the United States Eliav Benjamin said: "They understand that we are conducting the war in accordance with our interests. In the end of the day, we will do what we need to do when we need to do it."
Spreading violence
Fears that the Hamas-Israel war could mushroom into a wider Middle East conflict rose over the weekend with Washington warning of a significant risk to US interests in the region and announcing a new deployment of advanced air defences.
Along Israel's northern border with Lebanon, the Iran-backed Hezbollah group has clashed with Israeli forces in support of Hamas in the deadliest escalation of frontier violence since an Israel-Hezbollah war in 2006.
Early on Monday, Israeli aircraft struck two Hezbollah cells in Lebanon that were planning to launch anti-tank missiles and rockets toward Israel, the Israeli military said. Israel also struck other Hezbollah targets, including a compound and an observation post, it said.
Hezbollah said on Monday one of its fighters was killed, without providing details. Israel's military said seven soldiers have been killed on the Lebanese border since the latest conflict began.
Hezbollah is formed in 1982 after Israeli forces invaded southern Lebanon that year.
It is backed by Iran and leads a multi-party alliance that holds just under half the seats in Lebanon's parliament.
In the West Bank, two Palestinians were killed at the Jalazone refugee camp near Ramallah, the Palestinian health ministry said.
Residents told the Reuters news agency that Israeli forces raided the camp and made many arrests as they clashed with gunmen and some youths who threw stones. The Israeli army has not issued a statement about the incident.
Iranian security officials told Reuters Iran's strategy was for Middle East proxies like Hezbollah to pursue limited strikes on Israeli and US targets but to avoid a major escalation that would draw in Tehran.
A second convoy of humanitarian aid for the Gaza Strip entered the enclave via the Rafah border crossing on Sunday. Source: AAP / Mohammed Asad/AP
The United Nations humanitarian office said the volume of aid entering so far was just 4 per cent of the daily average before the hostilities and a fraction of what was needed.
The aid shipments did not include fuel.