U.S. President Donald Trump has threatened India with increased tariffs over its purchase of Russian oil amid Moscow's war in Ukraine.

Amid stiffening ties between US and India over Russian oil imports, National Security Adviser Ajit Doval arrived in Moscow for a visit aimed at strengthening ties between Russia and India.

Russian oil exporters are predicted to take in $153 billion this year, according to the Kyiv institute. Fossil fuels are the single largest source of budget revenue. The imports support Russia’s ruble currency and help Russia to buy goods from other countries, including weapons and parts for them.