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"I express my gratitude to the US for extending a helping hand to India when India was hit by the second wave of COVID-19," PM Modi said in the meeting with Ms Harris.
"India and America are natural partners; we have similar values, geopolitical interests, and our coordination and cooperation is also increasing," PM Modi said, and invited the US Vice President to India.
"When India experienced the surge of Covid, the United States was proud to support India in its need and its responsibility to vaccinate its people. I welcome India's announcement that it will soon be able to resume vaccine exports. It is particular note and admiration that India, I'm told, is currently vaccinating approximately 10 million people a day as of today," Ms Harris said.
The Prime Minister also held a bilateral meeting with his Japanese counterpart Yoshihide Suga. This was also PM Modi's first in-person meeting with Suga after the latter took over the reins from Shinzo Abe in September last year.
Earlier on Thursday, he met a group of five top American corporate leaders on a one-on-one basis from a range of diverse sectors ranging from drones to 5G, semiconductors, and solar and encouraged them to step up their investments by highlighting the vast opportunities in India.
He also held separate meetings with CEOs of Qualcomm, Adobe, First Solar, General Atomics and Blackstone. PM Modi, who arrived in Washington DC on Wednesday on an official visit to the US during which he will hold the first face-to-face meeting with President Joe Biden and Kamala Harris
Ahead of his meeting with the business leaders, PM Modi had said he would interact with leading CEOs to highlight economic opportunities in India.
"Talking technology...," the Prime Minister's Office said in a Twitter post after PM Modi's meeting with Qualcomm CEO Cristiano Amon and First Solar CEO Mark Widmar. They had a productive interaction, it said.
PM Modi's three-day Washington trip will be capped by a meeting with President Joe Biden at the White House on Friday. This is going to be the first in-person meeting between the two leaders after Mr Biden took over as the US President on January 20.
Mr Biden and PM Modi will also hold a "Quad" summit with the leaders of Australia and Japan, aiming to boost cooperation in the Indo-Pacific region amid China's growing dominance in the area.