The number of recorded Covid-19 infections in India climbed above 24 million on Friday amid reports that the highly transmissible coronavirus mutant first detected in the country was spreading across the globe.

The Indian B.1.617 variant of the virus has been found in cases in eight countries of the Americas, including Canada and the United States, said Jairo Mendez, a WHO infectious diseases expert.

People infected by the variant included travellers in Panama and Argentina who had arrived from India or Europe. In the Caribbean, cases of the Indian variant have been detected in Aruba, Dutch St Maarten and the French department of Guadeloupe.

The mutant strain has also been detected in Britain, as well as in Singapore.

"These variants have a greater capacity for transmission, but so far we have not found any collateral consequences," Mendez said. "The only worry is that they spread faster."

Public Health England said the total number of confirmed cases of the variant had more than doubled in the past week to 1,313 across the United Kingdom.

"We are anxious about it - it has been spreading," British Prime Minister Boris Johnson said, adding that there would be meetings to discuss what to do. "We're ruling nothing out," he added.

According to health ministry data, India recorded 4,000 deaths and 343,144 infections in the last 24 hours. It was the third consecutive day of 4,000 or more deaths but daily infections have stayed below a peak of 414,188 last week.

While the total number of recorded infections crossed 24 million, the number of people confirmed to have died from Covid-19 stood at 262,317 since the pandemic first struck India over a year ago.

But a lack of testing in many places meant a lot of deaths and infections were omitted from the official count, and experts say the real numbers could be five to ten times higher.

Bhramar Mukherjee, a professor of epidemiology at the University of Michigan, said most models had predicted a peak this week and that the country could be seeing signs of that trend.

Still, the number of new cases each day is large enough to overwhelm hospitals, she said on Twitter on Thursday. "The keyword is cautious optimism."

The situation is particularly bad in rural areas of Uttar Pradesh, India's most populous state with a population of over 240 million. Television pictures have shown families weeping over the dead in rural hospitals or camping in wards to tend the sick.

Bodies have washed up in the Ganges, the river that flows through the state, as crematoriums are overwhelmed and wood for funeral pyres is in short supply.

Clamour for vaccines

The second wave of infections, which erupted in February, has been accompanied by a slowdown in vaccinations, although Prime Minister Narendra Modi announced that vaccinations would be open to all adults from May 1.

India is the world's largest vaccine producer but has run low on stocks in the face of the huge demand. As of Thursday, it had fully vaccinated just over 38.2 million people, or about 2.8% of a population of about 1.35 billion, government data shows.

More than 2 billion doses of coronavirus vaccines will likely be available in India between August to December this year, top government adviser V.K.Paul told reporters amid criticism that the government had mishandled the vaccine plan.

Those doses would include 750 million of AstraZeneca's vaccine, as well as 550 million doses of Covaxin, made by Bharat Biotech.

“We are going through a phase of finite supply. The entire world is going through this. It takes time to come out of this phase,” Paul said.