Trump hails 'exceptional' Modi at India rally as protesters clash in Delhi

US President Donald Trump received a red-carpet welcome in India on Monday, addressing a huge rally at a mega cricket stadium on a maiden official visit to India that is big on photo opportunities but likely short on substance.

Visiting PM Narendra Modi's home state of Gujarat, Trump and First Lady Melania visited independence hero Mahatma Gandhi's ashram, where Modi gifted him a "see no evil, hear no evil, speak no evil" three wise monkeys statue.

The billionaire and the tea seller's son then headed to a new cricket stadium –– the biggest in the world –– where Trump heaped praise on Modi as an "exceptional leader, a great champion of India" in front of 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".

Trade tensions, Kashmir

Trade tensions have grown between the US and India, the world's fifth-biggest economy, as Trump's "America First" drive collides with PM Modi's protectionist "Make in India" mantra.

While sharing concerns about China and deepening their defence ties, India has bristled at Trump's offer to mediate in the Kashmir dispute with Pakistan and at unease in Washington over a citizenship law criticised as anti-Muslim.

"India is a country that proudly embraces freedom, liberty, individual rights, the rule of law, and the dignity of every human being," Trump said.

"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 fulfill 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 a wall that locals said was to hide a slum. Stray dogs, cows, and monkeys were also kept away.

'New initiatives'

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

Later Monday Trump and Melania –– dressed in an off-white jumpsuit and Indian sash alongside her husband in his usual suit and tie –– flew to the Taj Mahal for sunset before the main official talks on Tuesday.

Parts of the white marble "jewel of Muslim art", according to UNESCO, were given a mud-pack facial to remove stains, while efforts were made to lessen the stench of the adjacent river.

"We hope the US liberalises its visa regime for skilled workers. They need it and India has too many young skilled and talented people," said student Maunas Shastri.

'Tariff king' 

But behind the platitudes and apparent warm rapport between the two leaders lies a fraught relationship worsened by the trade protectionism of both governments.

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

Rather than a wide-ranging trade deal, reports said Trump and Modi may instead ink smaller agreements covering Harley-Davidson motorcycle imports and American dairy products, as well as defence pacts.

Also on the cards could be the supply of six nuclear reactors, the fruit of a landmark atomic accord in 2008.

An Indian government spokesman said the world's fifth-largest economy "would not like to rush into a deal", adding that the issues involved were "complicated".

"The big missing deliverable at least for now seems likely to be the one both countries had sought, which is the trade deal," Tanvi Madan from the Brookings Institution told reporters.

Other points of friction include defence, with Russia remaining India's biggest supplier despite a possible $2.4-billion deal for American helicopters.

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.

'We are concerned'

In Washington, India has faced criticism over its clampdown in restive Kashmir and a recently passed citizenship law that critics say is anti-Muslim and which has led to ongoing protests across the nation.

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".

"We are concerned... and I think that the president will talk about these issues in his meetings with Prime Minister Modi and note that the world is looking to India to continue to uphold its democratic traditions, respect for religious minorities," the official added.

Trump also ridiculed Modi last year for "constantly telling me he built a library in Afghanistan".

"That's like five hours of what we spend... And we are supposed to say, 'oh, thank you for the library'. I don't know who is using it in Afghanistan," Trump had said.

Unrest in New Delhi

Indian police used tear gas and smoke grenades in New Delhi on Monday to disperse thousands of people demonstrating for and against a new citizenship law just before Trump's maiden visit to the city.

Reuters news agency reporters saw multiple vehicles set on fire, metal barricades torn down and thick smoke billowing as thousands of supporters of the new law clashed with opponents, both sides hurling stones.

India's capital has been a hotbed of protest against the law, which eases the path to people from neighbouring countries to gain Indian citizenship.

This has led to accusations that Modi and his Hindu nationalist Bharatiya Janata Party (BJP) are undermining India's secular traditions.

The BJP denies any bias against India's 180 million-strong Muslim minority, but objectors have been camping out in several parts of New Delhi for two months.

At least half a dozen people were injured in Monday's violence, with police vastly outnumbered.

Local politician Yogendra Yadav urged police in a tweet to "prevent communal violence".

The clashes stretched over nearly a kilometre (half a mile) of road and lasted from early afternoon until well into the evening.

The protesters appeared to be divided along religious lines, and some pulled members of the media aside and asked them about their religion.

Monday's clashes were some of the worst seen in New Delhi since the protests against the Citizenship Amendment Act (CAA) began in early December.

"We are in support of the CAA. If they want to protest, they should go somewhere else," said a protester who gave his name only as Amit.

Trump is due in New Delhi later on Monday, where he will hold talks with Modi about 10 km (six miles) from the scene of the violence.