India, Jan. 6 -- A sharp new confrontation is brewing at the intersection of geopolitics, energy and trade, after US Senator Lindsey Graham claimed that India's Ambassador to the United States personally urged him to seek tariff relief from President Donald Trump in return for New Delhi cutting back on purchases of Russian oil.

Speaking aboard Air Force One on Sunday while accompanying President Trump, Graham said Ambassador Vinay Kwatra told him that India was deliberately reducing its intake of Russian crude and wanted Washington to ease the heavy tariffs imposed on Indian exports.

"I was at the Indian Ambassador's house about a month ago, and all he wanted to talk about was how they are buying less Russian oil," Graham said. "And he ...