WASHINGTON: US President Donald Trump welcomed Indian Prime Minister Narendra Modi to the White House for their first face-to-face meeting, seeking to forge a chemistry that can add new fizz to a flourishing relationship between the world's two largest democracies.

Despite differences over issues such as immigration and climate change, Modi is expected to assure Trump that the United States has nothing to fear from India's growing economic clout.

After they began their afternoon talks in the Oval Office likely to center on issues such as trade and war in Afghanistan, the two leaders are expected to give a joint statement to reporters.

Trump, who described Modi as a "true friend!" on Twitter after his weekend arrival in the US, should find much in common with the Indian leader, with both men having won power by portraying themselves as establishment outsiders.

While ties with some traditional allies have been strained by Trump's complaints that Washington has been the loser in trade agreements, Modi appears alert to his host's sensitivities and emphasis on transactional diplomacy.

Writing in a Wall Street Journal editorial published just ahead of their meeting, Modi said that in "an uncertain global economic landscape, our two nations stand as mutually reinforcing engines of growth and innovation."

"The transformation of India presents abundant commercial and investment opportunities for American businesses," said Modi whose government is about to implement a new nationwide tax system designed to scythe through red tape.

"The rollout of the Goods and Services Tax on July 1 will, in a single stroke, convert India into a unified, continent-sized market of 1.3 billion people," he wrote.

Busy day of meetings

Ahead of his talks with Trump, Modi met with Secretary of State Rex Tillerson and Defense Secretary Jim Mattis as India eyes the purchase of more military equipment from the US.

Although there are not expected to be any major defense announcements, the California-based contractor General Atomics said it had been given clearance by the US government to sell drones to the Indian army.

The State Department also announced that it was slapping sanctions on a senior figure in the Kashmiri group Hizb-ul-Mujahideen.

Syed Salahuddin (also known as Mohammed Yusuf Shah) was designated as a global terrorist.

Relations between India and the US were generally cool until the 1990s but they warmed under Trump's predecessor Barack Obama, as India sought greater foreign investment and trade ties.

But it was not long after Trump's election that obstacles emerged on issues such as trade and visas for Indians wanting to work in the United States.

Then Trump accused India of seeking to profit from the Paris climate accord as he announced the US withdrawal from the deal this month -- drawing sharp denials from New Delhi.

A proposed overhaul of H-1B visas -- used by thousands of Indian software engineers to work in the United States -- has caused concern in New Delhi.

But Indian officials have played down those differences, insisting that Modi was sensitive to his counterpart's concerns over American jobs and trade, and there were "no major sticking points" that could sour the talks.

"If there's one thing we want (from the talks), it's chemistry... If the chemistry is good, then frankly everything else gets sorted," a senior Indian official who is traveling with the prime minister told reporters in Washington.

Afghanistan on agenda

Regional security is expected to be high on the agenda as Washington considers deploying up to 5,000 extra troops in Afghanistan to help local forces fighting insurgent groups and seeks to encourage what an administration official describes as India's "positive role" in the country.