Eight countries - six of them in Africa, including Nigeria, Kenya and Lesotho - could soon run out of HIV drugs following the US government's recent decision to pause foreign aid, the UN World Health Organization (WHO) said.

US President Donald Trump announced the freeze on his first day in office in January as part of a review into government spending.

"Disruptions to HIV programmes could undo 20 years of progress," WHO chief Tedros Adhanom Ghebreyesus warned.

It could also lead to more than 10 million additional cases of HIV and three million HIV-related deaths, he added, noting this was "more than triple the number of deaths last year".

Nigeria, Kenya, Lesotho, South Sudan, Burkina Faso and Mali - as well as Haiti and Ukraine - would run out of live-saving anti-retroviral (ARV) medicines in the coming months, Dr Tedros said at a press conference on Monday.