WASHINGTON: Once shunned by the United States, Indian Prime Minister Narendra Modi rode a wave of enthusiasm and popular support Monday to the White House, where he has kicked off a two-day visit with President Barack Obama.

The two leaders sought to put a brave face on the relationship despite widespread concerns that US-Indian ties have frayed in recent years.

Modi's visit started with a private dinner with Obama on Monday evening, the day after thousands of Indian-Americans flocked to New York's Madison Square Garden for a rare chance to see the new leader of the world's largest democracy.

The dazzling Bollywood-style dancers and dozens of US lawmakers that took part in that event highlighted the rock star welcome that Modi is enjoying on his first official visit to the US since being elected in May.

It wasn't always so. When Modi requested a visa to visit the United States nearly a decade ago, Washington said no.

That rejection came three years after religious riots killed more than 1,000 Muslims in the state of Gujarat, where Modi was the top elected official. Another potential wrinkle in Modi's visit: A human rights group is offering $10,000 to anyone who can serve Modi with a summons issued by a federal court in New York to respond to a lawsuit the group filed accusing him of serious abuses.

The lawsuit is on behalf of two unnamed survivors of the violence. Modi has denied involvement in the violence and India's Supreme Court has said there was no case to bring against him.

As a head of state, Modi has immunity from lawsuits in US courts. And White House officials said they doubted the issue would cloud the visit. “Whether it's security and counter terrorism or strengthening the economy or a host of other regional issues, there is a broad framework where India and the US work closely together to advance our shared interests,” said White House spokesman Josh Earnest.

Obama and Modi broke the ice over dinner Monday as they sought to reinvigorate soured relations between their countries. Joining them in the Blue Room was Vice President Joe Biden, who was to attend a State Department lunch with Modi and Secretary of State John Kerry on Tuesday.

But there was one small issue: Modi is fasting to honour the Hindu goddess Durga and is consuming only water or lemon-flavoured water.

The White House said Modi's dietary needs would be accommodated, but offered no details. Obama's courtship of Modi will continue Tuesday with an Oval Office meeting, marking a rare second day of attention from Obama. During their talks, Obama and Modi will focus on economic growth and cooperation on security, clean energy, climate change and other issues, the White House said.

They will also address regional concerns, including Afghanistan, where the US is wrapping up its 13-year military involvement, and Syria and Iraq, where the US is ramping up its military engagement as Obama builds an international coalition to target Islamic State militants operating in the both countries.

Obama visited India in 2010 and held up the US-India relationship as the “defining partnership” of the 21st century. But the relationship has been lukewarm at best.

While military cooperation and US defence sales have grown, the economic relationship has been rockier, with Washington frustrated by India's failure to open its economy to more foreign investment and address complaints over intellectual property violations.

A landmark civil nuclear agreement exists between the two countries, but Indian liability legislation has kept US companies from capitalising on the deal.

Further fraying relations was the arrest and strip search last year in New York of an Indian diplomat on visa fraud charges.

A major aspect of this week's visit is the chance for Obama and Modi to begin building rapport, administration officials said.

Obama was among the first Western leaders to telephone Modi with congratulations after his Hindu nationalist Bharatiya Janata Party swept into power after May's landslide vote.

The visit also is a victory lap of sorts for Modi, a former tea seller.

“He's gone in just a matter of a few months from persona non grata to person of honour to be received warmly in the Oval Office,” said Milan Vaishnav, who studies South Asia at the Carnegie Endowment for International Peace, a Washington think tank.