The World Health Organization says studies suggest that about 40 percent of coronavirus infections are caused by people who carry the virus but show no symptoms.

The head of the WHO's Health Emergencies Programme, Michael Ryan, and the technical chief for coronavirus responses, Maria Van Kerkhove, disclosed this during a Q&A session on social media on Tuesday.

Van Kerkhove said some people who are asymptomatic can transmit the virus. She indicated those silent virus carriers are as infectious as carriers with symptoms.

She advised people in areas where infection is spreading to wear face masks when they cannot practice physical distancing.

Ryan noted that clusters of cases were found at gyms and karaoke clubs in Japan.

He pointed out that the virus is present in the upper respiratory tract close to the mouth, unlike MERS and SARS pathogens.

He added studies suggest that the virus can be transmitted when infected people speak loudly or breathe heavily during hard exercises.

Confirmed COVID-19 cases have exceeded 7.1 million globally, with over 407,000 fatalities and more than 3.3 million recoveries, according to the latest tally from Johns Hopkins University.

The U.S. now has over 1.9 million confirmed cases with the death toll at 111,000. Officials are worried a second COVID-19 wave could come during protests across the country over the police killing of George Floyd.

Russia has announced its first step to allow Russian citizens to travel beyond its borders and the mayor of Moscow said the capital's restriction on movement would end on Tuesday.

In France, Paris prosecutor has opened a probe into the country's handling of the COVID-19 crisis.

Nearly 7.2 million people have now been confirmed to have the coronavirus and nearly 409,000 have died, according to data from Johns Hopkins University. The US, the UK and Brazil have recorded the highest death tolls. The US, Brazil and Russia have the most cases.

Source: International News Agencies