Countries that fail to use every mechanism available to combat the still-raging novel coronavirus will struggle to beat it, the World Health Organization (WHO) said on Wednesday.

"Some countries ... have taken a fragmented approach. These countries face a long, hard road ahead," Director-General Tedros Adhanom Ghebreyesus told a virtual briefing from the WHO headquarters in Geneva, without singling out any nations.

More than 10.5 million people have been infected globally and more than 500,000 have died since COVID-19 first emerged.

He said local flare-ups were inevitable as some nations began lifting lockdown restrictions. "But countries that have the systems in place to apply a comprehensive approach should be able to contain these flare-ups locally and avoid reintroducing widespread restrictions," he said.

WHO emergencies expert Mike Ryan told the same briefing that the UN body planned to send two experts from its headquarters to join its country team in China, to establish the scope for a mission looking into the origins of the coronavirus.

China has said it was transparent throughout and would support an investigation once the pandemic is under control.

Ryan said the WHO was trying to verify reports of hoarding of medical supplies in the U.S. – which has the world's highest COVID-19 death toll at more than 127,000 – and wanted to ensure everyone has access to life-saving materials.

Asked about a virus in Chinese pigs that a study said has become more infectious to humans and might become a "pandemic virus," Ryan said: "It's important to reassure people that it is not a new virus and is a virus under surveillance."

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