The coronavirus outbreak was Wednesday declared a pandemic by the World Health Organisation (WHO), whose chief expressed his "deep concern" over "alarming levels of inaction" in combating the virus spread.

WHO chief Dr Tedros Adhanom Ghebreyesus said the number of cases outside China had increased 13-fold over the past two weeks.

However, he clarified that the labelling of it as a pandemic, or a disease spreading in multiple countries around the world simultaneously, did not mean the WHO was changing its advice about what countries should do and he called on governments to change the course of the outbreak by taking "urgent and aggressive action", the BBC reported.

"Several countries have demonstrated that this virus can be suppressed and controlled.

"The challenge for many countries who are now dealing with large clusters or community transmission is not whether they can do the same - it's whether they will," he said, noting that the governments had to "strike a fine balance between protecting health, minimising disruption and respecting human life".