Large crowds of the Indian diaspora on Thursday gathered at the South Lawns of the White House under an overcast sky as ceremonial music played ahead of Prime Minister Narendra Modi's arrival here for his official welcome.

Officials said anywhere between 2,000-3,000 persons are expected to witness the ceremonial welcome being given to Modi, who is on his first state visit to the US.

A drizzle was no dampener to the enthusiasm of the members of the diaspora, many of whom travelled overnight from different parts of the US, as they waved the flag of the two countries and raised slogans.

"What a great sight it is. It is like a festival," Hitesh Shah, who came from Boston, said.

Slogans like 'Vande Mataram', 'Bharat Mata ki Jai' and 'Modi, Modi' went up the air amid a mood of cheer.

Prime Minister Modi arrived here on Wednesday on the second leg of his maiden state visit to the US during which he will hold bilateral talks with President Joe Biden and address a joint session of the US Congress.

Prime Minister Modi and President Biden will have a one-on-one meeting in the Oval Office of the White House on Thursday before holding high-level talks to further boost the growing Indo-US strategic relations in areas like defence, space and critical technologies.

The day would begin with President Biden and First Lady Jill Biden greeting Prime Minister Modi for the Official Arrival Ceremony on the South Lawn which includes a 21-gun salute.

Vice President Kamala Harris and the Second Gentleman Doug Emhoff would be attending the welcome ceremony. Thereafter, the leaders of the two largest democracies of the world will hold a bilateral meeting in the Oval Office, where they are expected to make some opening remarks.

Modi and Biden are scheduled to address a news conference together from the East Room of the White House.

They are likely to take questions from journalists. Normally each side takes two questions, but sometimes it can be one from each side. During the last Indian State Visit of former prime minister Manmohan Singh in November 2009, the two sides took one question each.

The prime minister would then head to the Congress to deliver an address to the joint meeting of the US Congress, which would be attended by Congressmen and senators in the presence of several hundred Indian Americans from the visitor’s gallery.

When Modi addresses a joint meeting of the US Congress today, it will make him only the third world leader, outside of Israel, to make such an address twice.

The other two are Winston Churchill in 1941, 43 and 1952 and Nelson Mandela in 1990 and 1994. Modi earlier addressed the US Congress in 2016.

Biden and the first lady will greet Modi on arrival for the State dinner in the evening. A tent pavilion is being installed on the South Lawns of the White House, big enough to accommodate more than 400 guests.

The guest lists would be announced about an hour before the reception and the dinner, which would be followed by entertainment. While the two sides have managed to keep the deliverables a closely guarded secret, it is expected that India and the US would emerge as best friends after the visit.

The major areas include space, education, defence, technology, climate change and health.