The official also noted that the Indian Mission in the United States and Air India are getting requests and inquiries from donors based in the United States to transport not just concentrators but also other medical supplies including oxymeters.

"The Indian American community, NGO's and individual are inquiring about the logistics of ways to reach out to those who are impacted the most by the pandemic in India," the source added.

Earlier in the day, US president Joe Biden said that the United States is determined to "help" India as it faces an unprecedented Covid-19 crisis.

"Just as India sent assistance to the United States as our hospitals were strained early in the pandemic, we are determined to help India in its time of need," Biden tweeted.

The United States has announced that it will provide the raw material required for the Indian manufacture of the Covishield vaccine to India.

The announcement was made after National Security Advisor Jake Sullivan spoke on the phone with Indian counterpart Ajit Doval, expressing deep sympathy for the people of India following the recent spike in Covid-19 cases.

According to a readout from The White House, Sullivan affirmed America's solidarity with India. US and India are the two countries with the greatest number of Covid-19 cases in the world.

India on Sunday reported 3,49,391 new Covid-19 cases and 2,767 deaths in the last 24 hours. According to the Union Health Ministry, five states -- Maharashtra, Uttar Pradesh, Karnataka, Gujarat and Kerala -- contribute 54 per cent of the cases.

Millions of Americans are not getting the second doses of their Covid-19 vaccines, and their ranks are growing. More than five million people, or nearly 8% of those who got a first shot of the Pfizer or Moderna vaccines, have missed their second doses, according to the most recent data from the Centres for Disease Control and Prevention. That is more than double the rate among people who got inoculated in the first several weeks of the nationwide vaccine campaign. The CDC’s count of missed second doses is through April 9.

The reasons vary for why people are missing their second shots. In interviews, some said they feared the side effects, which can include flulike symptoms. Others said they felt that they were sufficiently protected with a single shot. Another hurdle has been surprisingly prevalent. A number of vaccine providers have cancelled second-dose appointments because they ran out of supply or didn’t have the right brand in stock.

Cases Remain High In US

Vaccination rates are falling in the US, despite the spread of highly contagious virus variants. More than 50,000 new US cases were reported on Saturday, and case rates are similar to those of the second wave last summer. But the average number of vaccine doses being administered each day, which rose for months and peaked at 3.4 million, has now fallen to 2.9 million, its lowest level since March 31, according to data from the CDC. The vaccination rate stopped climbing on April 13, when health officials recommended pausing the use of Johnson & Johnson’s vaccine to allow researchers to examine a rare blood-clotting disorder that emerged in six recipients. The FDA lifted the pause on Friday.