The head of the Serum Institute of India, the world's largest vaccine manufacturer, has urged US President Joe Biden to remove an embargo on the export of materials he said was hindering production of doses, APA reports citing BBC.
Adar Poonawalla tweeted the president's official Twitter account calling for the two countries to "truly unite in beating this virus".
He did not provide details about the materials required.
Poonawalla said recently that production capacity at his institute - which produces the Novavax and Oxford-AstraZeneca vaccines - was "very stressed" and he urged more vaccine makers to ramp up production.
The Serum Institute said earlier this month that it had been providing 65-70 million doses every month to India, and exported a total of nearly an equal amount of doses since it began production early this year.