Zambia's foreign minister has warned diplomats against interfering in the country's affairs, days after the US ambassador raised concerns about the "systematic theft" of drugs donated to the southern African state.

Mulambo Haimbe said there was an "increasing tendency" by envoys to ignore diplomatic channels, and this could undermine the "spirit of mutual respect".

He did not name anyone, but his comments were seen as being directed at the US ambassador to Lusaka, Michael Gonzales.

Last week, Gonzales called a press conference to announce that the US was cutting $50m (£37m) of health aid to Zambia because of the theft of life-saving medications that the US had provided for patients.

He added that he had decided to go public after holding more than 30 fruitless meetings with senior Zambian officials.

In his response, Haimbe said that addressing the government through the media amounted to interference and was in breach of diplomatic conventions.

"We remain open to addressing any matters of concern through appropriate diplomatic channels," the minister added.

Last week, the US embassy said it had presented its findings of the alleged corruption to Zambian officials in April last year, and had offered help to stop further theft and to bring the culprits to justice.

However, no action was taken by the Zambian authorities, it added.

On Monday, Zambia's Home Affairs Minister Jacob Mwiimbu said that a forensic audit on the alleged theft had been completed and handed over to security agencies for further action.

About 75 people have been arrested in a countrywide crackdown that saw more than 400 health facilities raided over the alleged scam, he said.

"There will be no sacred cows in this pursuit," Mwiimbu added.

Gonzales said that an inspection carried out by US officials at more than 2,000 pharmacies last year had found that most were selling drugs and medical supplies donated by the US.

Zambia's Health Minister Elijah Muchima earlier said the problem of theft predated the current government, which took office in 2021.

Muchima also said several Zambian officials had been sacked following the thefts identified by the US, and that "an advanced digital stock tracking system" had been set up to monitor the supply of medicines.

The cut in US assistance, expected to take effect next year, would affect drugs to treat malaria, HIV and TB.

But the health minister has reassured Zambians that there were sufficient stocks of all drugs so there was "no immediate risk of shortages".

Gonzales said the recent US measure was separate to the foreign aid freeze announced by President Donald Trump in January.

The freeze has affected health programmes across Africa, including shipments of critical medical supplies, among them HIV drugs.

In March, Zambia's President Hakainde Hichilema said Trump had "slapped us on both cheeks", saying it was time for his country to strengthen its treasury to procure its own medicines.

The US accounts for about a third of public health spending in Zambia, according to the US embassy.