The coronavirus pandemic is at a "critical phase" in the Asia-Pacific region, the World Health Organization (WHO) said Wednesday, urging action to limit transmission and avoid more dangerous variants from emerging.

Takeshi Kasai, regional director for WHO’s Western Pacific region, noted that the number of COVID-19 cases and deaths in Asia-Pacific countries "are rising sharply" mainly due to the highly contagious delta variant of the coronavirus.

In the first three weeks of August, the region accounted for 10% of global COVID-19 cases and more than 8% of global deaths, he said.

"At this critical phase in the pandemic, let us stay the course working together," he said in an online press conference.

"It is within our power to reduce the threat of the virus by making the most of every tool we have to fight it today," he added.

With the surges being experienced by several countries in the region, two scenarios were possible in the coming months, Kasai said.

The first scenario is one where the risk of COVID-19 is reduced and can be managed like seasonal influenza and other vaccine-preventable diseases with vaccinations, prevention measures and short, targeted measures against flare-ups, he said.

"The second scenario is where other more dangerous variants are able to evolve, variants that spread even more easily, cause more severe diseases or are resistant to existing vaccines," he said.

"This scenario and all of the associated health, social and economic costs is ... the one we want to avoid if possible," he added.

"The best way we can do this is by doing everything we can to limit the transmission now," he urged.