In a televised address on Wednesday evening, Benjamin Netanyahu said he will be held accountable for the October 7 massacre by Hamas which killed 1,400 people and saw more than 200 taken hostage, but only after Israel's war against the Islamic militant group.
He said the decision on when forces would go in would be taken by the government's special war cabinet.
"We have already killed thousands of terrorists and this is only the beginning," Mr Netanyahu said.
"Simultaneously, we are preparing for a ground invasion. I will not elaborate on when, how or how many. I will also not elaborate on the various calculations we are making, which the public is mostly unaware of and that is how things should be."Mr Netanyahu also expressed sorrow for the attack, saying October 7 "is a black day in our history". "We will get to the bottom of what happened on the southern border around Gaza. This debacle will be investigated. Everyone will have to give answers, including me," he told the nation.
The Israeli leader also warned people in Gaza to move to the south and encouraged Israeli citizens to carry arms, adding that the government was doing everything possible to bring hostages home.
His national address came as Israel's UN ambassador repeated calls for UN chief Antonio Guterres to resign, after he defended his comments that the Hamas attacks "did not happen in a vacuum" made to the Security Council on Tuesday.
Speaking on Wednesday to "set the record straight", the UN secretary-general said he was "shocked" that parts of his statement to the council were misrepresented "as if I was justifying acts of terror by Hamas".
"This is false. It was the opposite," Mr Guterres told reporters, reiterating his condemnation "unequivocally of the horrifying and unprecedented October 7 acts of terror by Hamas in Israel."But Israel's UN ambassador Giled Erdan countered that the secretary-general "once again distorts and twists reality," pointing again to his statement on Tuesday that the October 7 massacres "did not happen in a vacuum.""Every person understands very well that the meaning of his words is that Israel has guilt for the actions of Hamas or, at the very least, it shows his understanding for the 'background' leading up to the massacre," the Israeli ambassador said.UN spokesman Stephane Dujarric said anyone who listened to the secretary-general in the council Tuesday and earlier Wednesday knows that his position is "there is no justification for — the horrendous and abhorrent acts of terrorism perpetrated by Hamas on the seventh of October."Ms Dujarric said Mr Guterres stands by his words and "is not going to respond to one member state's call to step down."
Israel stepped up bombings of south Gaza, killing many Palestinians, officials said on Wednesday.
Hundreds of thousands of Palestinians fled from north to south in Gaza after Israel warned them it would bombard mainly the north to wipe out Hamas militants.
Forty-four people were injured in an air strike near an UNRWA school in Rafah, which was sheltering 4,600 people, the UN agency for Palestinian refugees in the Gaza Strip said.
The overall Palestinian death toll now exceeds 6,500, the health ministry in Hamas-ruled Gaza said on Wednesday.
It came as a a United Nations vote on humanitarian pauses in Gaza failed to pass on Wednesday evening.The US resolution called for the consideration of humanitarian pauses to allow for the flow of aid into Gaza, but the idea was vetoed by Russia and China.
Russia said on Tuesday it would not support the plan and put forward its own resolution calling for a humanitarian ceasefire. It also failed.
The United Arab Emirates also voted no, while 10 members voted in favour and two abstained.
The first UK RAF flight providing medical and water supplies to Gaza was sent to Egypt on Wednesday.
Aid agencies continue to cry out for a humanitarian ceasefire, with a third of Gaza’s hospitals and nearly two-thirds of primary health care clinics closing services entirely due to damage from air strikes and a lack of fuel.
Al-Awda hospital, one of the biggest in Gaza and the main provider of maternity services in the north, will run out of fuel on Wednesday evening, ActionAid UK said.
A doctor at the hospital Khaled, said: "We lack medicines, especially emergency and anaesthesia drugs. We will have to stop the activities if we do not receive more fuel. We are working on two generators alternatively. There has been no electricity at all for 17 days in Gaza.
"Capacity is a problem because there are a huge number of patients and not enough beds.
"All the hospitals around here are overcrowded. I cannot move any patients. We are insisting on staying in our hospital so we can continue to provide services for our patients, our injured, and our people."