By Sanjeev Miglani and Manoj Kumar

NEW DELHI (Reuters) - U.S. President Donald Trump's son dropped a planned speech on foreign affairs in the Indian capital on Friday after ethics experts said he should avoid wading into policy issues as a private citizen.

Donald Trump Jr. is on a tour of India to promote real estate projects in several cities but ethics watchdog groups in the United States say there is a possible conflict of interest in pushing the Trump brand name while his father is in the White House.

He was billed to make a speech on the topic "Reshaping the Indo-Pacific - The New Era of Cooperation" but hours before the conference began that was changed into a "fireside chat" where he spoke about his business and stayed clear of policy issues.

"I am here on business, I am not representing anyone," he said at the conference organized by the Economic Times, a leading newspaper, and Yes Bank.

He spoke before Prime Minister Narendra Modi delivered a keynote speech on preparing India for the future to a gathering of business leaders from India and overseas.

U.S. Senator Bob Menendez, the top Democrat on the Senate Foreign Relations Committee, wrote to the U.S. ambassador to India this week to ask for guarantees that the embassy and the State Department will not offer any support to Trump Jr. beyond helping the U.S. Secret Service to provide him with security.

Trump Jr. said he had been coming to India for more than a decade to build business for The Trump Organisation and it had reached a take-off stage but there were self-imposed curbs following the election of his father as president.

"I learnt about doing business here through the school of hard knocks, we have built partnerships here," he said.

This week he was wooing buyers to book luxury apartments in Trump Towers in Gurgaon on the outskirts of New Delhi as well as in Mumbai, attending champagne receptions.

Trump's partners in India are playing up the Trump brand. In the days leading up to Trump Jr.'s visit, one of its development partners in Gurgaon began an advertising campaign in newspapers offering dinner and conversation with the president's son.

Story continues

But Trump said his company could not build on the gains it had made in India because of the curbs over the past year.

"Ten years of hard work to get there, this would be a time to capitalize, but its a sacrifice, its a big sacrifice," he said. "But we will be back, once we are out of politics."

Shortly before taking office last year, Trump Sr. said he would hand off control of his business empire, which includes luxury homes and hotels across the world, to his sons Donald and Eric, and move his assets into a trust to help ensure that he would not consciously take actions as president that would benefit him personally.

Several government and private ethics watchdogs said he should have gone further, divesting himself of assets that could cause a conflict of interest.

(Reporting by Sanjeev Miglani and Manoj Kumar; Editing by Matthew Mpoke Bigg)