US Vice President Kamala Harris expressed "deep concern" over the situation faced by Gaza's civilians in talks Monday with Israeli war cabinet member Benny Gantz, who is in Washington on a visit that lacks the approval of Prime Minister Benjamin Netanyahu.

A day after she delivered some of the harshest US criticism of "Israel" since the war began, Harris called for "Israel" to let in more aid to the Gaza Strip, while also urging the Palestinian Resistance group Hamas to accept a six-week ceasefire deal.

Gantz, who left the political opposition to join the war cabinet after October 7, has been at odds with Israeli occupation Prime Minister Benjamin Netanyahu on releasing captives held by the Palestinian Resistance and finding an exit strategy from the war.

His independent visit to the United States reportedly infuriated Netanyahu and prompted the Prime Minister's office to express frustration and emphasize that the Minister's trip goes against the Israeli government's regulations.

Netanyahu's associates also conveyed that "the Prime Minister has made it clear to Gantz that the State of Israel only has one Prime Minister."

Israeli media reported that the Israeli Ambassador to the United States, Mike Herzog, will not deal with Gantz's visit and will miss the meetings he will hold with Biden administration officials per Netanyahu's orders.

The media mentioned that the Israeli government refused to pay for the expenses of Gantz's trip because it was not approved by Netanyahu s a diplomatic trip.

Similar to the situation in Washington, the Israeli Embassy in London has received instructions not to provide assistance to Gantz during his visit to the UK.

Gantz is scheduled to meet with British Foreign Minister David Cameron to address various topics, including discussions on thwarting an initiative in the country aiming to impose a weapons embargo on "Israel", according to the Israeli Channel 12.

'Deep concern' about humanitarian conditions in Gaza

"The vice president expressed her deep concern about the humanitarian conditions in Gaza," Harris' office said in a statement, adding that she "urged Israel to take additional measures" to increase the flow of aid.

But the statement also mentioned that Harris "welcomed Israel’s constructive approach" to the prisoner exchange negotiations and "called on Hamas to accept the terms on the table."

Gantz, who is also meeting with National Security Adviser Jake Sullivan and Secretary of State Antony Blinken, said on the way into the White House that "with friends, we should always speak openly, and that's what we're going to do."

The White House played down suggestions the talks could exacerbate tensions with Netanyahu, saying Gantz had requested the meeting while passing through Washington.

"Israel" had presented a "forward leaning" proposal for the ceasefire which it was now up to Hamas to accept, US National Security Council spokesman John Kirby told reporters on Monday.

On Sunday Harris called for an immediate ceasefire, underlining that "Israel" had "no excuses" for not letting in more aid.

The next day she denied any discord between herself and Biden, as her remarks went further than the president had previously gone in criticizing "Israel".

"The president and I have been aligned and consistent from the very beginning," Harris told reporters.

Read more: 'Israel' deliberately attempting to exacerbate famine: Gaza Media