India has approved US drug maker Merck's antiviral drug for emergency use to treat coronavirus patients.

Health minister Mansukh Mandaviya tweeted on Tuesday that molnupiravir will be "manufactured in the country by 13 companies for restricted use under emergency situation" for high-risk adult patients.

Merck says clinical tests show that the pill can cut the risk of hospitalization by 30 percent among high-risk adults if administered within five days of the onset of symptoms.

India's approval comes after the US Food and Drug Administration issued an emergency-use authorization for the drug on Thursday.

Japan's health ministry also approved the pill on Friday as the first oral coronavirus drug in the country.

Along with molnupiravir, India approved two homegrown coronavirus vaccines for emergency use.

India's daily case counts exceeded 400,000 during the second wave of the outbreak that began in April.

The government is stressing that medical services are well prepared in a bid to ease public concerns over a possible third wave.