US Republican presidential candidate Donald Trump pledged that the United States and India would be "best friends" if he is elected and that he would boost intelligence sharing with India in the battle against militants.

Trump spoke at an event sponsored by the Republican Hindu Coalition to raise money for victims of terrorism. It featured Bollywood-style performers who danced in colourful, traditional costumes.

"If I'm elected president, the Indian and Hindu community will have a true friend in the White House, that I can guarantee you," said Trump, who noted that as a real estate developer he has two "massive developments" in India.

Indian Prime Minister Narendra Modi has developed a friendly relationship with President Barack Obama, a Democrat who wants Trump's opponent, Hillary Clinton, to win the Nov. 8 election.

"We will defeat radical Islamic terrorism when I’m president. We will stand shoulder to shoulder with India in sharing intelligence and keeping our people safe mutually," said Trump.

He called India a strategic ally and that "we will be best friends" if he wins the election.