US President Donald Trump landed in the western Indian city of Ahmedabad on Monday at the start of a visit during which the two sides will aim to reset relations that have been buffeted by a trade spat.
India and the United States have built close political and security ties and Trump's two-day trip is a sign of their converging interests, officials say, including a way to counter China's rise as a superpower.
Prime Minister Narendra Modi was at the airport to greet Trump and his wife, Melania, as they stepped off Air Force One.
A road show is planned and a huge reception will be held in a 110,000-seat cricket stadium in the city which is the political home of Modi. A huge crowd has filled the stadium, claimed to be the world's biggest cricket ground.
In the stadium, many people were wearing customised white hats saying "Namaste (Greetings) Trump", while workers handed out thousands of cardboard masks of the US president.
"We are ready to come to India, we are on our way, we will be meeting everyone in a few hours," Trump tweeted in the Hindi language before he landed.
Modi tweeted in response: "The guest is God".
Modi, who has built a personal rapport with Trump, is pulling out the stops for Trump's visit even though a trade deal that Washington was pushing for has run into problems.
The rally in Ahmedabad will be a larger version of the "Howdy Modi" rally that Trump and Modi jointly appeared at in Houston to a jubilant crowd of 50,000 Indian Americans last year, where Trump likened Modi to Elvis Presley for his crowd-pulling power.
His entourage includes daughter Ivanka and son-in-law Jared Kushner besides members of his cabinet, including Commerce Secretary Wilbur Ross.
Many roads were blocked off in Ahmedabad, shops shut and police stationed on rooftops and balconies. School children boarded buses bound for the stadium shouting "We love Trump." Others were carrying Indian flags.
"I have been here since 7 a.m. I don't know how many I have handed out," said Durvin Prajapati, a 19-year-old volunteer who was standing on the stadium concourse with a box of two thousand Trump masks. "We like Trump: he is good for business"
ADMIRES MODI'S ABILITY
Trump, who seeks re-election in November, routinely gets the biggest audience of any candidate in the US presidential race, ranging up to 20,000 or so, and he has been grudgingly admiring of Modi's ability to get a bigger crowd than him.
From Ahmedabad, he heads to Agra for a sunset visit to the iconic Taj Mahal mausoleum, before landing in New Delhi for a summit with Indian officials and business leaders.
But the prospects of resolving a wrangle over trade that led to both countries imposing retaliatory tariffs remains elusive. Indian and US officials have both said progress is unlikely to be made until after the US election.
The two sides have been arguing over US demands for access to India's poultry and dairy markets, Indian price controls on medical devices such as stents and stringent local data storage rules that US technology firms say will raise the cost of doing business.
Modi's government has sought restoration of trade concessions that Trump withdrew in 2019 and greater access to US markets for its pharmaceutical and farm products.
The two countries are expected to announce defence deals including an Indian navy plan to buy helicopters from Lockheed Martin worth $2.6 billion.