An explosive public feud has broken out this week between the United States and Zambia.

The two nations were negotiating a deal to provide billions of dollars in U.S. health funding, but the outgoing U.S. ambassador publicly accused the Zambian government last week of graft and negotiating in bad faith.

Zambia’s foreign minister fired back on Monday, accusing the United States of linking aid to access to the critical minerals of the southern African nation.

The tussle spotlights the Trump administration’s push to overhaul U.S. foreign aid, replacing the foreign assistance provided by the United States Agency for International Development with an “America First” alternative. Mr. Trump, along with tech tycoon Elon Musk, dismantled the aid agency last year, accusing it of being wasteful.

The Trump administration has said countries should shoulder more of their own health funding, and that about two dozen African countries have already signed agreements. But a number have also walked away, citing the United States’ request for private health data, among other issues.

Zambia, Ghana and Zimbabwe have all turned down the Trump administration. Kenya signed, but the deal is being held up in court.

“Any deal that is exchanging human lives for access to critical minerals is immoral,” said Jonas Chanda, the former Zambian health minister.