US President Donald Trump on Wednesday ordered steeper tariffs on Indian goods over New Delhi's continued purchase of Russian oil, opening a new front in his trade wars hours before another wave of duties takes effect.

The additional 25-percent tariff on Indian goods, coming into place in three weeks, stacks atop a separate 25-percent duty entering into force Thursday, taking the level to 50 percent for many products.

Trump's order also threatens penalties on other countries who "directly or indirectly" import Russian oil, a key revenue source for Moscow's war in Ukraine.

Exemptions remain however for goods targeted under sector-specific duties such as steel and aluminum, and categories that could be hit later, like pharmaceuticals and semiconductors.

Smartphones are in this list of ex

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