President Joe Biden is facing questions from some in his Democratic party about the amount of aid the US sends to Israel.
Senator Bernie Sanders has said the US must take a "hard look" at how the money is spent.
So what does Israel get and what is it used for?
How much aid does the US give?
In 2020, the US gave $3.8bn (£2.7bn) in aid to Israel - part of a long-term, yearly commitment made under the Obama administration. Almost all of this aid was for military assistance.
This support came as part of an agreement signed by former president Barack Obama in 2016 for an overall package of $38bn (26.8bn) in military aid over the decade 2017-2028.
This represents an increase of about 6% (adjusted for inflation) over the spending commitment for the previous decade.
On top of this, last year the US gave $5m (£3.5m) toward resettling migrants in Israel. The country has a long-standing policy of accepting Jews from other parts of the world as citizens.
How has Israel used US money?
Over the years, US aid has helped Israel develop one of the most advanced militaries in the world, with the funds allowing them to purchase sophisticated military equipment from the US.
For example, Israel has purchased 50 F-35 combat aircraft, which can be used for missile attacks - 27 of the aircraft have so far been delivered, costing around $100m (£70.4m) each.
Last year Israel also bought eight KC-46A Boeing 'Pegasus' aircrafts for an estimated $2.4bn (£1.7bn). These are capable of refuelling planes such as the F-35 in mid-air.
Of the $3.8bn given to Israel in 2020, $500m (£353.9m) was for missile defence, including investments in Israel's Iron Dome and other systems which can intercept incoming rockets.
Since 2011, the US has contributed a total of $1.6bn (£1.1bn) to the Iron Dome defence system.
In addition, Israel has spent millions collaborating with the US on developing military technology, such as a system to detect underground tunnels used to infiltrate Israel.
The Israeli government invests heavily in military equipment and training, using the aid to compensate for being smaller than many other regional powers.
How does this compare with other countries?
Since World War Two, Israel has been the largest overall recipient of US foreign aid.
In 2019, the most recent year to publish fully reported figures, Israel was the second highest recipient of US foreign aid after Afghanistan, according to USAID.
A lot of the money given to Afghanistan has gone towards supporting the US military's efforts to stabilise the country, which has been engulfed by war since the US invasion in 2001.
But with US troops set to leave Afghanistan by September this year, only about $370m (£261m) has been requested for 2021.
Israel receives by far the most money in the Middle East.
Egypt and Jordan are also major recipients of US aid. Both have their own peace deals with Israel, having once fought wars with it.
They each received around $1.5bn (£1.1bn) worth of US aid in 2019.
Meanwhile, President Biden has restored some funding ($235m) for the UN agency which helps Palestinian refugees. This funding was cut by the Trump administration in 2018.
Why does the US give Israel so much aid?
There are a number of reasons why the US gives so much aid to Israel, including historic commitments dating back to US support for the creation of the Jewish state in 1948.
Moreover, Israel is seen by the US as a crucial ally in the Middle East - with shared goals and a mutual commitment to democratic values.
The US Congressional Research Service says: "US foreign aid has been a major component in cementing and reinforcing these ties.
"US officials and many lawmakers have long considered Israel to be a vital partner in the region."
The US government's foreign assistance agency says: "US assistance helps ensure that Israel maintains its Qualitative Military Edge (QME) over potential regional threats."
It also states: "US assistance... is aimed at ensuring that Israel is sufficiently secure to take the historic steps necessary to reach a peace agreement with the Palestinians and for comprehensive regional peace."
Ensuring Israel can defend itself against threats in the region has been cornerstone of US foreign policy for both Democratic and Republican presidents for decades.
The 2020 Democrat party election platform expressed "ironclad support" for Israel, but some on the left of the party are now questioning the US aid commitment.
Senator Sanders and other Democrats have moved to try to halt the planned sale of $735m (£518m) worth of precision-guided weapons to Israel.