It's no secret US President Donald Trump is not a fan of foreign aid.

Early on in his campaign for the top job, he was quoted saying America should stop foreign aid to "countries that hate us".

Now, he's issued a similar threat to countries if they vote in favour of a UN General Assembly vote asking it to withdraw it's decision to recognise Jerusalem as Israel's capital.

So which countries actually receive aid from the US?

Key points: Warning letter reportedly sent to more than 180 countries a day before the vote

Warning letter reportedly sent to more than 180 countries a day before the vote Countries asked to acknowledge the historical friendship, partnership, and support US has extended

Countries asked to acknowledge the historical friendship, partnership, and support US has extended Trump: "Let them vote against us. We'll save a lot."

What is the US currently giving and why is this a big deal?

A lot.

Numbers from 2015 show the US was the largest single donor country of foreign aid in the world.

The Security Assistance Economic Aid dashboard shows this year the US spent $18.25 billion in economic aid to 92 recipients, and $18.23 billion in security aid to 143 recipients.

[Recipients includes individual countries, international organisations, and groups of countries.]

In a story for The Conversation earlier this year, Georgia State University's Joannie Tremblay-Boire, said only countries considered low and middle-income, based on their gross national income, were eligible for the money, which totalled $43 billion in 2015.

And she said while it seemed like a lot, it accounted for about 1 per cent of the total US budget.

Any cuts could have big impacts internationally.

"While taxpayers are spending just a few bucks each on ODA [official development assistance], the impact is profound, saving millions of people from hunger, averting the worst of natural disasters like droughts and flooding, tackling life-threatening diseases like tuberculosis and malaria, and more," she wrote.

"Military aid includes military financing, which our allies use to buy weapons, funding intended to advance counterterrorism and anti-narcotics initiatives, and money spent on efforts related to military operations in Iraq, Afghanistan and other nations."

Who is getting the most?

In terms of regions, the Middle East and North Africa receive the most of the economic assistance.

The Sub-Saharan Africa region receives $US1.2 billion — 25.32 per cent of the budget.

In terms of individual countries, the following receive the most in economic [not security] aid:

Afghanistan ($US650,000,000)

Afghanistan ($US650,000,000) Jordan ($US635,800,000)

Jordan ($US635,800,000) Kenya ($US632,500,000)

Kenya ($US632,500,000) Tanzania ($US534,500,000)

Tanzania ($US534,500,000) Uganda ($US435,500,000)

Uganda ($US435,500,000) Zambia ($US428,525,000)

Zambia ($US428,525,000) Nigeria ($US413,300,000)

In terms of security aid, the countries receiving the most help are:

Afghanistan ($US5 billion)

Afghanistan ($US5 billion) Israel ($US3.2 billion)

Israel ($US3.2 billion) Iraq ($US1.3 billion)

Iraq ($US1.3 billion) Egypt ($US1.3 billion)

Egypt ($US1.3 billion) Syria ($US541,500,000)

Syria ($US541,500,000) Jordan ($US364,200,000)

Hasn't Mr Trump cut foreign aid anyway?

Yep.

It was a key component of his first budget with the State Department and US Agency for International Development budget cut by almost 30 per cent.

The document, dubbed America First, A Budget Blueprint to Make America Great Again, said it would include "deep cuts to foreign aid".

"It is time to prioritise the security and wellbeing of Americans, and to ask the rest of the world to step up and pay its fair share," the statement read.

He reiterated this rhetoric in a Washington Post interview.

"But you look at some of our inner cities," Mr Trump said.

"And yet you know I watched as we built schools in Iraq and they'd be blown up.

"And we'd build another one and it would get blown up … And yet we can't build a school in Brooklyn.

"We have no money for education, because we can't build in our own country.

"And at what point do you say, 'Hey, we have to take care of ourselves'?"

What has the US said ahead of the UN vote?

Well, the US has sent a warning letter to most of the 193 UN member states, and Mr Trump confirmed its position to reporters.

"They take hundreds of millions of dollars and even billions of dollars, and then they vote against us," he told reporters at the White House.

"Well, we're watching those votes.

"Let them vote against us. We'll save a lot. We don't care."

The US ambassador to the United Nations took to Twitter to back the President.

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