By Krishna N. Das, David Brunnstrom and Shivam Patel NEW DELHI/WASHINGTON (Reuters) -U.S. President Donald Trump's tirade against India over trade and Russian oil purchases threatens to undo two decades of diplomatic progress,

India, which now faces among the highest tariff rates imposed by the US, called the levy "unjustified and unreasonable".

Tariffs on Indian exports to the United States will surge to 50 percent by late August, as part of an effort by President Trump to pressure Russia into resolving its war in Ukraine.