US President Donald Trump said on Wednesday that imports from India will face 25 percent tariffs, while also announcing an unspecified "penalty" for New Delhi's purchases of Russian weapons and energy.

The measures will kick in on Friday, Trump posted on his Truth Social platform.

"Remember, while India is our friend, we have, over the years, done relatively little business with them because their tariffs are far too high, among the highest in the world, and they have the most strenuous and obnoxious non-monetary trade barriers of any country," Trump said.

He also posted in an all-caps message that the United States has a "massive" trade deficit with India.

He added that India has "always bought a vast majority of their military equipment from Russia, and are Russia's largest buyer of ENERGY, along with China, at a time when everyone wants Russia to STOP THE KILLING IN UKRAINE."

Trump did not specify what the penalty he referred to for Russia trade will be.

The measure comes as the US president signalled he intends to tighten US pressure on Moscow to halt fighting in Ukraine and negotiate a peace deal. On Tuesday, Trump said he was giving Russian President Vladimir Putin 10 days, which would mean the end of next week, to change course in Ukraine or face unspecified punishment.

India, the world's most populous country, was one of the first few major economies to engage Washington in broader trade talks.

But six months later, Trump's sweeping demands and India's reluctance to fully open its agricultural and dairy sectors have so far prevented New Delhi from sealing a deal that would shield it from punitive tariffs. (AFP)