Ukraine's foreign minister condemned India's ramping up of Russian oil purchases following Moscow's invasion as "morally inappropriate" in an interview broadcast Tuesday.
A day earlier India's top diplomat had defended the purchases of discounted Russian crude, saying Europe's imports still dwarfed those of his country despite the continent's efforts to reduce its dependence.
But Ukraine's Dmytro Kuleba told Indian broadcaster NDTV it was "completely wrong" to justify buying oil from Russia "by arguing that Europeans were doing the same".
It was "morally inappropriate", he said.
"Because you are buying cheap oil not because of Europeans but because of us, of our suffering, of our tragedy, and because of the war that Russia launched against Ukraine."
India has increased its purchases of cheap Russian oil six-fold since the invasion in February, to the extent that Moscow is now its top crude supplier, according to local media reports.
The government says that with millions of poor Indians hit hard by the global rise in commodity prices in the wake of the war, it has no choice but to buy the cheapest oil possible.
On Monday, India's foreign minister S. Jaishankar said his country's costs were being driven up by European countries now buying up more oil and gas from the Middle East.
"The Middle East was traditionally a supplier for an economy like India, so it puts pressure on prices in the Middle East as well," Jaishankar told reporters.
India and Russia are long-standing allies dating back to the Cold War. Moscow remains New Delhi's biggest weapons supplier and India has abstained on UN resolutions condemning the invasion of Ukraine.
Prime Minister Narendra Modi did however tell Vladimir Putin in September at a regional forum that the "era of war" was over, in comments seen as a rebuke to the Russian president.