WASHINGTON, United States (AFP) — The United States (US) foreign aid agency formally closed down Tuesday, with President Donald Trump’s administration trumpeting the end of the “charity-based model” despite predictions that millions of lives will be lost.

Founded in 1961 as John F Kennedy sought to leverage aid to win over the developing world in the Cold War, the US Agency for International Development (USAID) has now been incorporated into the State Department — after Secretary of State Marco Rubio slashed 85 per cent of its programming.

In a farewell to remaining staff on Monday, former presidents George W Bush and Barack Obama — as well as U2 frontman Bono — saluted their work and said it was still needed.

Bush pointed to PEPFAR, the massive US effort to fight HIV/AIDS that he considers one of the top achievements of his 2001-2009 Republican presidency.

“This programme shows a fundamental question facing our country — is it in our nation’s interest that 25 million people who would have died now live? I think it is,” Bush said in a video message seen by AFP.

Obama, who like Bush has been sparing in openly criticising Trump, said that ending USAID was “inexplicable” and “will go down as a colossal mistake.”

“Gutting USAID is a travesty and it is a tragedy because it’s some of the most important work happening anywhere in the world,” the Democrat said.

A study published in the medical journal The Lancet predicted that more than 14 million people would die, a third of them small children, by 2030 due to the foreign aid cuts.

Rubio painted a drastically different picture of USAID, which was an early target of a sweeping government cost-cutting drive led for Trump by billionaire Elon Musk.

Rubio said that USAID’s “charity-based model” fuelled “addiction” by developing nations’ leaders and that trade was more effective.

“Beyond creating a globe-spanning NGO industrial complex at taxpayer expense, USAID has little to show since the end of the Cold War,” Rubio wrote in an essay.

He also complained that many recipients of US aid do not vote with the United States at the United Nations and that rival China often enjoys higher favourability among the public.

A senior State Department official, speaking on condition of anonymity, said that The Lancet study relied on “incorrect assumptions” and said the United States will continue aid but in a “more efficient” way.

He said that PEPFAR will remain, with a priority on stopping HIV transmission from mothers to children.

But he acknowledged the United States was no longer funding PrEP medication, which significantly reduces the rate of HIV transmission and has been encouraged by high-risk communities.

“No one is saying that gay men in Africa shouldn’t be on PrEP. That’s wonderful. It doesn’t mean that the United States has to pay for every single thing,” the official said.

He said the Trump administration was looking at “new and innovative solutions” and pointed to food deliveries in war-battered Gaza staffed by US military contractors and surrounded by Israeli troops