The United States has criticised Zambia for failing to engage on a new health aid agreement governing more than $1 billion in U.S. funding, saying ​repeated outreach from Washington had been ignored as an April 30 deadline ‌passed without a deal.

Outgoing U.S. ambassador Michael Gonzales said the failure to finalise the memorandum of understanding (MoU) had left funding ongoing on an ad hoc basis, without a coherent implementation plan for programmes covering HIV, malaria, maternal and child health, and disease preparedness.

"Instead ​of continuing to languish without engagement, the actual funding under our Health ⁠MOU should have started this month," Gonzales said in remarks delivered on Thursday ​evening as he prepared to leave the post.

Health advocates have warned that the deal links the money to access to mining and poses data-sharing risks. Gonzales rejected what he called "disgusting and patently false" allegations that Washington was threatening to withhold life-saving healthcare support "unless we get critical minerals."

Zambia's ​presidential spokesperson, Clayson Hamasaka, said the government would engage with Washington through diplomatic ​channels.

"We appreciate the support we have received from the U.S. and other countries...If there are any ‌concerns, ⁠we are open to dialogue, but that should be done through laid-down diplomatic channels," Hamasaka said in response to Gonzales' remarks.

The stalled deal has become a flashpoint after Washington earlier cut aid over the theft of donated medicines, underscoring governance ​concerns in Zambia's health ​system.

The agreement also ⁠requires about $340 million in co-financing from the Zambian government over the same period, according to a draft reviewed by Reuters.

Gonzales said Washington had faced "effectively zero substantive engagement" from Zambian officials since January, with calls going unanswered and meetings cancelled, preventing meaningful negotiations on future cooperation.

The agreement had been due to be signed in November, but stalled after revised drafts were circulated.

Gonzales said the ⁠U.S. ​would continue to honour its long-standing commitment to ​the Zambian people, including providing antiretroviral drugs and preventing mother-to-child HIV transmission, but warned that large-scale aid would ​depend on concrete reforms.