Prime Minister Benjamin Netanyahu has said Israel will launch an invasion of the southern Gaza city of Rafah regardless of truce talks with Hamas.
It comes amid ongoing attempts to try to reach an agreement for a ceasefire and hostage releases.
But at a meeting of hostages' relatives, Mr Netanyahu said he would invade "with or without" a deal.
His comments follow renewed warnings by the US against a Rafah invasion unless civilians were properly protected.
In a phone call with Mr Netanyahu on Sunday, US President Joe Biden "reiterated his clear position" on Rafah, a White House statement said. Mr Biden has previously described an invasion of Rafah as a "red line".
On Tuesday, UN Secretary General Antonio Guterres said an assault on Rafah would be an "unbearable escalation", appealing for "all those with influence over Israel to do everything in their power to prevent it".
More than half of Gaza's 2.5m population is in Rafah, having fled there to escape fighting in other parts of the territory. Conditions in the overcrowded city are dire, and displaced people there have spoken of a lack of food, water and medication.
The West Bank-based Palestinian President Mahmoud Abbas said on Monday that an invasion of Rafah would be the "biggest catastrophe in the Palestinian people's history".
Israeli sources told the Reuters news agency on Monday that plans to attack Rafah would be shelved in favour of a "sustained period of calm" if a ceasefire agreement between Hamas and Israeli was reached.
Days earlier, Israel's Foreign Minister Israel Katz told Israeli Channel 12 television that "if there will be a deal, we will suspend the [Rafah] operation".
But on Tuesday Mr Netanyahu insisted that the war would continue until Israel had achieved all of its objectives in Rafah.
"The idea that we will halt the war before achieving all of its goals is out of the question," he said.
"We will enter Rafah and we will eliminate the Hamas battalions there with or without a deal, in order to achieve the total victory," according to a statement issued by Mr Netanyahu's office.
It said the families urged the prime minister and his national security adviser, Tzachi Hanegbi, to continue the war and ignore mounting international pressure. Many hostage families however have publicly demonstrated for the government to agree to a deal to return their loved ones at any cost.
About 130 hostages from among 253 kidnapped by Hamas during its unprecedented attack on Israel on 7 October remain unaccounted for. At least 34 of them are presumed dead. The rest have been released or rescued.
Indirect talks have been at an impasse for weeks, although the US Secretary of State, Antony Blinken, said on Monday that he hoped Hamas would accept what he has called Israel's "extraordinarily generous offer" for a truce.
Meanwhile the head of the UN's refugee organisation has warned that the looming invasion was causing people in Rafah to live in a state of "constant traumatic stress disorder".
"People have not yet been asked to evacuate from Rafah, but there is a sense that if there is no deal this week that could happen," Philippe Lazzarini told reporters.
"My colleagues on the ground are describing constant state of trauma among the people."
Mr Netanyahu also denounced as "a scandal on a historical scale" recent reports, citing Israeli officials, that the International Criminal Court (ICC) at The Hague could be preparing to issue arrest warrants for Israeli government leaders and military commanders on charges related to the war.
"I want to make one thing clear: no decision, neither in The Hague nor anywhere else, will harm our determination to achieve all the goals of the war," the prime minister said.
"Israel expects the leaders of the free world to come out strongly against this scandalous step, a step that will harm the self-defence capacity not only of the State of Israel, but of all democracies in the world."
There has been no announcement from ICC Prosecutor Karim Kahn KC.
However, his office has been formally investigating alleged war crimes in the Israeli-occupied West Bank, East Jerusalem and Gaza Strip since June 2014, and Mr Khan has confirmed that the investigation will cover the 7 October attack and the ensuing war.
Israel has never ratified the Rome Statute, the ICC's founding treaty, and Mr Netanyahu insisted that the ICC had "no authority" over the country. However, the ICC ruled in 2015 that it had jurisdiction because the Palestinians had ratified the treaty.
White House Press Secretary Karine Jean-Pierre said on Monday that the US - which has also not ratified the Rome Statute - did not believe the court has jurisdiction and did not support the investigation.
