US President Joe Biden told Israeli Prime Minister Benjamin Netanyahu on Monday that he is "deeply concerned" about military operations in the southern Gaza city of Rafah, where more than a million Palestinians are seeking refuge.
"The President has rejected, and did again today, the straw man that raising questions about Rafah is the same as raising questions about defeating Hamas. That's just nonsense," White House National Security Adviser Jake Sullivan told reporters.
"Our position is that Hamas should not be allowed a safe haven in Rafah or anywhere else, but a major ground operation there would be a mistake.
"It would lead to more innocent civilian deaths, worsen the already dire humanitarian crisis, deepen anarchy in Gaza and further isolate Israel internationally."
The two leaders have not spoken in more than a month, with the last call taking place on February 15, marking a change in US-Israeli relations.
Mr Biden over the past month has said that he would not support an Israeli invasion of Rafah without a clear plan for the safety of civilians, once declaring it a "red line".
The White House says that Israel has not presented such details yet.
The UN estimates at least 1.4 million people, including those who were forcibly displaced from northern and central parts of Gaza, are now cornered in Rafah, which Israel claims hosts some members of Hamas.
Mr Sullivan said Mr Biden asked Mr Netanyahu to send a senior Israeli interagency delegation to Washington to hear his administration's concerns, and he agreed.
"The President explained why he is so deeply concerned about the prospect of Israel conducting major military operations" in Rafah, Mr Sullivan said.
"More than a million people have taken refuge in Rafah, they went from Gaza City, to Khan Younis, and then to Rafah.
"They have nowhere else to go. Gaza's other major cities have largely been destroyed.
"And Israel has not presented us or the world with a plan for how they would safely move those civilians, let alone feed and house them and ensure access to basic things like sanitation."
Benjamin Netanyahu: 'We will finish the job in Rafah'
The Biden administration has lent large amounts of support to Israel after Hamas launched a deadly attack in October, where Israeli authorities say about 1,200 were killed.
Israeli forces have launched military operations on the Gaza Strip in the months since, resulting in more than 31,700 people killed, according to the Gaza Health Ministry.
"More innocent civilians have died in this conflict in this military operation than in all the wars in Gaza combined, including thousands of children," Mr Sullivan said.
The call on Monday is also the first time they have directly communicated since they disputed publicly over comments about how Israel's war on Hamas in Gaza was really helping the country – given the high civilian death toll – and not being able to reach a ceasefire by the start of Ramadan.
But Mr Sullivan also confirmed that Israel has "made significant progress against Hamas", including killing Hamas's number three leader Marwan Issa in an operation last week.
"They've broken a significant number of Hamas battalions, killed thousands of Hamas fighters, including senior commanders," he said.
