In June last year, United States President Donald Trump had called Prime Minister Narendra Modi a 'true friend'. About a year later, the US has warned India by saying that its decision to purchase oil from Iran is "not helpful". As India has subtly put forward that it will continue to purchase oil from Iran despite the sanctions\u00a0kicking-in on November 4, the US has said that it is reviewing the decision "very carefully", news agency PTI reported. Oil Minister Dharmendra Pradhan earlier this week had said that two refiners have already placed orders for importing crude oil from Iran in November. India has also been mulling to pay Iran for crude oil in the rupee. In May, Trump had re-imposed economic sanctions on Iran by withdrawing the 2015 nuclear accord. Iran was the third largest exporter of oil to India in\u00a0Q1FY19 with\u00a08.1 million tonnes of crude oil exports. "And India will find out. We'll see. So I'm not going to get ahead of him (Trump), but certainly, when we hear about things such as purchasing oil or the S-400 systems, it's not helpful. The United States government just reviews that very carefully," US State Department spokesperson Heather Nauert was quoted as saying by PTI. Meanwhile, Indian refined have already placed demand for additional crude oil supply of\u00a0our million barrel from Saudi Arabia, which may help compensate for fall in imports from Iran. Prime Minister Narendra Modi is also said to have been holding a high-level meeting to discuss ways to cut overall oil imports by 10%, the target for which is 2022. India imports roughly 80% of its total crude oil consumption.