US President Donald Trump on Thursday said that researchers should try to apply their findings to coronavirus patients by inserting ultraviolet light or disinfectant into their bodies.

The coronavirus appears to weaken more quickly when exposed to sunlight, heat and humidity, a US official said at a White House news briefing, in a potential sign that the pandemic could become less contagious in summer months.

"Is there a way we can do something like that by injection, inside, or almost a cleaning?" said Trump.

US government researchers have determined that the virus survives best indoors and in dry conditions, and loses potency when temperatures and humidity rise - and especially when it is exposed to sunlight, said William Bryan, acting head of the US Department of Homeland Security's Science and Technology Directorate.