Prime Minister Benjamin Netanyahu said Israel will defend itself "alone," if necessary, after Washington threatened to withhold further arms should Israeli troops begin a large-scale push into the southern Gaza Strip city of Rafah.
"If we have to stand alone, we will stand alone," he said in a video message released on Thursday.
He said Israel would fight "with our fingernails" to win, in his first public statement after the White House said it would restrict arms supplies in the case of a broader attack on Rafah.
Israeli operations in Rafah are so far mainly limited to the east of city, where an evacuation order was issued at the start of the week.
The US is Israel's main backer but President Joe Biden threatened to further restrict supplies if Netanyahu goes ahead with a major offensive. Israel says the Rafah operation is aimed at eliminating the Palestinian extremist organization Hamas.
Such a ground invasion would target the densely crowded area in which some 1.5 million of Gaza's roughly 2.2 million people have been seeking refuge from Israeli bombardment elsewhere in Gaza.
Military spokesperson Daniel Hagari said Israel has enough weapons and ammunition.
"The army has weapons for the missions it plans and also for the missions in Rafah. We have what we need," Hagari said at a press conference after being asked about Biden's remarks.
"The US has provided unprecedented security assistance to the state of Israel and the military during the war," he said, adding that differences are resolved behind closed doors.
Meanwhile, the US military said the weeks-long construction of a temporary port for delivering badly needed aid to Gaza is nearly complete.
The two key parts of the port, a floating jetty and another causeway, have been completed, US Department of Defence spokesman Pat Ryder said in Washington on Thursday.
"While I'm not going to provide a specific date, we expect these temporary piers to be put into position in the very near future, pending suitable security and weather conditions," he said.
Earlier, a US freighter carrying hundreds of tons of aid for the civilian population in Gaza left the Cypriot port of Larnaca.
Ryder said the cargo would be loaded onto another ship near the Israeli port of Ashdod and taken to the floating pier as soon as it was operational.
In future, freighters are to bring aid supplies directly from Cyprus to the floating pier, where the goods are to be loaded onto other boats then taken to another point along the coast.
The Pentagon says around 90 lorry loads per day are to reach the Gaza Strip via the floating pier initially, with up to 150 lorry loads per day are expected at a later date.
On the diplomatic front, representatives from Palestinian militant group Hamas and mediator Qatar left the Egyptian capital on Thursday after talks seeking a ceasefire and hostage release deal with Israel, sources at the Cairo airport said.
There was no immediate word on the outcome of the latest round of negotiations, although reports of the departures sparked concerns for the prospects for an agreement.
Hamas confirmed its team’s departure from Cairo heading for Doha, where the group’s political bureau is based.
The White House later confirmed that CIA chief William Burns, who was involved in the Cairo talks as part of a frenzy of shuttle diplomacy in recent days, had also left the Egyptian capital.
"His departure does not connote the end of the current round of negotiations," national security spokesman John Kirby said.
Israel and Hamas do not negotiate directly, so the US, Qatar and Egypt are acting as mediators, attempting to halt the conflict that has led to the deaths of nearly 35,000 people in the coastal strip.
The Palestinian territory has been the target of a massive Israeli air and ground offensive since the October 7 terrorist attacks led by Hamas, which killed 1,200 in southern Israel. Hamas took around 250 people hostage, some of whom have been released. It is unclear how many of the remaining hostages are still alive.
In Israel, there was further comment on Biden's threat of an arms freeze.
Far-right Israeli National Security Minister Itamar Ben-Gvir wrote on X on that Hamas loves Biden, using a red heart emoji. Later, the Israeli president and opposition politicians criticized Ben-Gvir for endangering Israel with such statements.
The US government had already decided last week to withheld a delivery of ammunition because of Israel's actions in Rafah.
US media reported that the delivery comprised 3,500 bombs, including 2,000-pound bombs.
According to analysts, Israel is using these in the fight against Hamas, for example to destroy the Islamists' underground tunnels.