New York/Washington | US President Donald Trump has said Prime Minister Narendra Modi "knew he was not happy" with India's purchases of Russian oil and that Washington can raise tariffs on New Delhi “very quickly”.

These remarks were made by President Trump while talking to reporters on Sunday aboard Air Force One en route to Washington DC from Florida.

"They (India) wanted to make me happy, basically. Modi is a very good man; he is a good guy. He knew I was not happy, and it was important to make me happy. They do trad,e and we can raise tariffs on them very quickly. It would be very bad for them," Trump said.

Trump's remarks came after US Senator Lindsey Graham, accompanying him on Air Force One, said that the tariffs imposed on India by Trump are the "chief reason" New Delhi is now buying substantially less Russian oil.

Graham spoke about his tariff bill that seeks to impose 500 per cent levies on imports from countries buying Russian oil.

Graham said that to end the Russia-Ukraine conflict, pressure must be put on Russian President Vladimir Putin's customers.

Trump said that the sanctions are hurting Russia very badly and then mentioned India. Graham then said that the US put a 25 per cent tariff on India for buying Russian oil.

"I was at the Indian Ambassador's house about a month ago and all he wanted to talk about is how they are buying less Russian oil. 'Would you tell the President to relieve the tariff? Graham said.