A day after U.S. President Donald Trump warned India of higher tariffs over its continued purchase of Russian oil, the Kremlin has hit back, calling such threats "illegal."

Responding to Trump’s remarks, Kremlin spokesperson Dmitry Peskov said on Tuesday that pressuring countries to stop trading with Russia is against international norms. "We hear many statements that are in fact threats, attempts to force countries to cut trade relations with Russia. We do not consider such statements to be legal," Peskov told reporters.

He added that sovereign nations have the right to decide their own trade and economic partnerships based on national interest, and attempts to interfere in these decisions would be seen as threats.

Trump, on Monday night, issued a fresh warning to India, claiming that New Delhi’s ongoing oil trade with Moscow—and the resale of that oil for profit—is fueling Russia’s war in Ukraine. He announced plans to substantially raise tariffs on Indian goods entering the U.S. if the purchases don’t stop.

“India is not only buying massive amounts of Russian oil, they are then, for much of the oil purchased, selling it on the open market for big profits. They don’t care how many people in Ukraine are being killed by the Russian War Machine,” Trump said in a social media post.

The Indian government responded strongly, calling the criticism “unjustified and unreasonable.” In a statement issued by the Ministry of External Affairs, India emphasized its right to safeguard its national interests and economic security, like any other major economy.

The tension comes just as a new 25% tariff from the U.S. on Indian goods came into effect on August 1. Trump has accused India of maintaining what he called the "highest tariffs in the world" on American imports.

The diplomatic spat marks a fresh round of strain in U.S.-India relations, with Russia stepping in to defend its trading partner and pushing back against what it sees as Washington’s unilateral pressure tactics.