Trump Hails 'Exceptional' Modi At Huge India Rally

US President Donald Trump got a rapturous and romantic welcome to India on Monday, addressing a huge rally and holding hands with his wife at the Taj Mahal, in a maiden official visit big on photo opportunities but short on concrete results.

Casting a cloud over Prime Minister Narendra Modi's welcome, however, a policeman and at least three civilians were killed in clashes in New Delhi over a contentious citizenship law hours before the US president was due in the Indian capital.

At the world's biggest cricket stadium in Modi's home state of Gujarat in western India, Trump heaped praise on the Indian right-winger as an "exceptional leader, a great champion of India", before a crowd of around 100,000.

"America loves India. America respects India, and America will always be faithful and loyal friends to the Indian people," Trump told the ecstatic crowd, many in Trump-emblazoned baseball caps.

Name-checking Bollywood films and Indian cricketers, Trump -- with an eye on elections in November -- paid tribute to the four-million-strong Indian-American diaspora as "truly special people".

"President Trump's visit opens a new chapter in our relationship -- a chapter that will document the progress and prosperity of the people of America and India," Modi said.

"The whole world knows what President Trump has done to fulfil the dreams of America."

Excited spectators had queued from 4:00 am for the "Namaste Trump" rally, reciprocating a "Howdy Modi" event in Houston last year where Trump likened Modi to Elvis.

Workers rushed to finish the stadium and erect a wall along the route that locals said was to hide a slum. Stray dogs, cows and monkeys were also kept away.

"Events like these will galvanise people to start to cooperate in new initiatives," said Pramit Maakoday, an Indian-American in the stadium.

Before the speech, Trump and First Lady Melania visited independence hero Mahatma Gandhi's ashram, where Modi gave him a "see no evil, hear no evil, speak no evil" three wise monkeys statue.

Later Trump and Melania -- in an off-white jump suit and sash alongside her husband in a buttercup-yellow tie -- flew to the Taj Mahal for a pre-sunset tour.

Then they headed to Delhi ahead of the main talks on Tuesday.

Parts of the Taj Mahal, the marble monument to love that UNESCO calls a "jewel of Muslim art", were given a mud-pack facial to remove stains, while efforts were made to lessen the stench of the adjacent river.

Behind the platitudes and blossoming bromance between the two leaders lies a fraught relationship as Trump's "America First" drive collides with Modi's "Make in India" mantra.

Trump has imposed tariffs on Indian steel and aluminium and suspended duty-free access for certain goods, prompting India to raise duties on US produce such as almonds.

The US leader has called India the "tariff king", and said before his visit that Asia's third-largest economy had been "hitting us very, very hard for many, many years".

Rather than a wide-ranging trade deal, reports said Trump and Modi may instead sign smaller agreements covering products such as Harley-Davidson motorcycles and US dairy products.

"We are in the early stages of discussions for an incredible trade agreement," Trump told the rally, calling Modi a "very tough negotiator".

"I am in no rush," he told reporters later.

With the US and India sharing concerns about China, the two men were expected to sign a number of defence deals during the visit, and to discuss the supply of six nuclear reactors.

Russia, however, remains India's biggest supplier in arms, with India having agreed to buy Moscow's $5.4-billion S-400 missile defence system despite the threat of US sanctions.

The US has pressured India to stop buying Iranian oil, while US businesses have raised concerns over New Delhi's plans to force foreign firms to store Indian consumers' personal data inside the country.

India has bristled at Trump's offer to mediate in the Kashmir dispute with Pakistan which a year ago again brought the two nuclear-armed neighbours close to war.

In Washington, India has faced criticism over its clampdown in restive Kashmir, and the recently passed citizenship law that has led to protests across the nation, including in New Delhi on Monday.

A senior US administration official told reporters Trump would raise concerns about religious freedom in the Hindu-majority nation during the trip, "which is extremely important to this administration".

"That's like five hours of what we spend," Trump said.