Indian opposition leader Rahul Gandhi on Tuesday denounced an "ideological war" in the South Asian country, ruled by Prime Minister Narendra Modi and his Hindu nationalist party.

Rahul Gandhi said there were "two completely different visions" between his Congress party and Modi's Bharatiya Janata Party (BJP) as he spoke to the National Press Club in the US capital Washington.

"We believe in a plural vision, a vision where everybody has a right to thrive... an India where you're not persecuted because of what religion you believe in, or what community you come from, or which language you speak," he said.

Gandhi, 54, was appointed in June to lead India's opposition in parliament, a key post that had been vacant for a decade.

In Washington, Gandhi said India had a problem with participation of weaker castes, pointing in particular to Dalits -- the once so-called "untouchables" in India's caste system.

"So there is a very small percentage of India which is controlling the entire infrastructure," Gandhi said.

He also criticised Modi's handling of relations with China,.

"We've got Chinese troops occupying land the size of Delhi. I think that's a disaster. I don't think Mr Modi's handled China well at all," he said.