US President Donald Trump's doubling of tariffs on imports from India to as much as 50% took effect as scheduled on Wednesday, Reuters reports.

This has delivered a serious blow to ties between the two countries that became strategic partners after the turn of this century.

A punitive 25% tariff imposed due to India's purchases of Russian oil adds to Trump's prior 25% tariff on many imports from India.

This is among the highest tariffs imposed by the US and on par with Brazil and China.