The US military is to set up a temporary port in Gaza so that more aid can get into the beleaguered territory by sea, President Joe Biden will say in his State of the Union speech on Thursday.
The move will not involve any US boots on the ground in Gaza, however, as military personnel will stay offshore while other allies are involved, senior administration officials said.
"We're not waiting on the Israelis. This is a moment for American leadership," one official told reporters, amid growing frustration in the White House with Israel's failure to allow more relief into the territory.
"Tonight the president will announce in his State of the Union address that he has directed the US military to undertake an emergency mission to establish a port in Gaza," the official said.
"This port, the main feature of which is a temporary pier, will provide the capacity for hundreds of additional truckloads of assistance each day."
US officials said it would take a "number of weeks" until the "significant capability" was able to bring more aid to desperate Gazans.
The aid will come via a maritime corridor bringing aid by sea from the port of Larnaca, on the Mediterranean island of Cyprus.
News of the new aid route comes despite months of the US heavily backing Israel in its devastating war on Gaza.
US officials were careful to stress that American troops would not be on the ground in Gaza, which has been under relentless Israeli bombardment for more than 150 days.
They did not specify exactly how the port would work without American personnel on the ground in Gaza, but implied that "partners and allies" plus the UN and aid groups would be involved on shore.
"The US military has unique capabilities. And they can do things from just offshore that are extraordinary and so that is the concept of operations that the president has been briefed on," a second official said.
A third official said the plan "involves the presence of US military personnel on military vessels offshore but it does not require US military personnel that go ashore to install the pier, or causeway facility".
The Israelis had been informed and the US would work with them on security requirements, they added.
The announcement during the key State of the Union speech underscores the acute political pressure Biden is under for his staunch support for Israel, despite the mounting Gaza death toll and humanitarian crisis.
Biden announced last week that the US was beginning airdrops of aid to Gaza, following an Israeli massacre that killed more than 100 people at an aid station in the north of the territory.
Israel's war on Gaza has so far killed 30,800 people. Israeli forces have attacked hospitals, ambulances and residential buildings in a military campaign that has prompted widespread hunger.
Efforts to reach a six-week ceasefire in the strip were continuing, with officials reiterating that the "onus is on Hamas" to agree to release Israeli hostages captured in the attack.
Hamas said on Wednesday that it had shown flexibility in trying to reach an agreement with Israel via mediators for a ceasefire in Gaza before Ramadan begins.
The group accused Israel of evading parts of an agreement that would lead to a permanent ceasefire.
On Thursday, Hamas's delegation voiced dissatisfaction with Israeli responses so far and left Cairo for consultations with the movement's leadership in Qatar.
Egypt's Al-Qahera News channel said the talks will now resume "next week".
US ambassador to Israel Jack Lew denied the talks had "broken down".
"The differences are being narrowed. It's not yet an agreement. Everyone's looking towards Ramadan, which is coming close. I can't tell you that it will be successful, but it is not yet the case that it is broken down," Lew said.