India vowed on Thursday to protect its labour-intensive agriculture sector, a central sticking point in bogged-down trade talks with the U.S., as Washington threatened 25% tariffs, triggering outrage from the opposition and a slump in the rupee.

The US will impose 25% tariffs on goods imported from India "plus an unspecified penalty" for buying Russian oil and weapons, President Donald Trump has said.

The president said Wednesday that imports from India would be subject to a 25 percent tariff as of Friday, as trade talks between the countries hit a stumbling block.