World Health Organization's (WHO) Director General Tedros Adhanom Ghebreyesus has noted China and South Korea as countries with significant declines in COVID-19 cases.

"Of the 118,000 COVID-19 cases reported globally in 114 countries, more than 90 percent of cases are in just four countries, and two of those China and South Korea – have significantly declining epidemics," Tedros said in a press briefing in Geneva, Switzerland, on Wednesday.

He noted that the number of cases outside China had increased 13-fold in the past two weeks, and the number of affected countries tripled. He said there were more than 118,000 cases in 114 countries, and 4,291 people who have lost their lives.

At the briefing, the WHO chief declared the COVID-19 outbreak a pandemic, making it the first coronavirus to prompt such a move by the body.

While acknowledging that some countries had not reported any cases of COVID-19, Tedros urged all countries to take part in the fight to stop the spread of the virus.

"81 countries have not reported any COVID-19 cases, and 57 countries have reported 10 cases or less. We cannot say this loudly enough, or clearly enough, or often enough: all countries can still change the course of this pandemic," he said.

The WHO chief warned that the body was expecting an increase in the number of COVID-19 cases and deaths in the coming weeks, but noted that concerted efforts would help contain the spread.

"If countries detect, test, treat, isolate, trace, and mobilize their people in the response, those with a handful of COVID-19 cases can prevent those cases becoming clusters, and those clusters becoming community transmission," Tedros said.