The World Health Organization (WHO) is urging all sexually active gay men to take antiretroviral drugs to reduce the spread of HIV.

The organisation says the move may help prevent a million new HIV infections over 10 years.

Officials warn rates of HIV in this group remain high across the globe.

But activists suggest this could discourage the use of condoms - one of the best methods to stop the virus spreading.

According to the WHO report, men who have sex with men are 19 times more likely to have HIV than the general population.

'Exciting approach'

Health experts say offering antiretroviral drugs to all at-risk men - known as pre-exposure prophylaxis - will provide an additional way to prevent infection, together with condom use.

When taken consistently by people at high risk, studies show the medication can reduce the chances of getting HIV by up to 92%.

And scientists say encouraging this group of men to take these pills could lead to a 25% reduction in new cases across the globe.

Dr Rosemary Gillespie, of the Terrence Higgins Trust, said: "We already know if someone has HIV, using treatment drastically reduces the likelihood of them passing it on, as does using condoms.

"The idea of treatment as prevention is not new, but the idea of extending treatment to HIV-negative people from high-risk groups is.

"Pre-exposure prophylaxis is an exciting approach, and likely to be one of a number of ways in which we can reduce the spread of HIV in the future.

"However, we need to evaluate how effective it will be in preventing HIV among gay men."

'Progress threatened'

She says until the results of UK trials are known, condoms and regular testing remain the best weapons against HIV and other sexually transmitted infections.

And while the number of people dying of Aids is falling sharply, the WHO says key populations need more attention.

According to the report, transgender women are almost 50 times more likely to have HIV than other adults, a level similar to that seen among people who inject drugs.

And sex workers are 14 times more likely to have HIV than the general population.

"Dr Gottfried Hirnschall of the World Health Organization said: "Failure to provide services to the people who are at greatest risk of HIV jeopardises further progress against the global epidemic and threatens the health and well-being of individuals, their families and the broader community."