New Delhi, July 22 -- US President Donald Trump has announced a phased tariff plan on imported generic medicines that will escalate duties to 200% by 2029 if foreign manufacturers-led by India's multi-billion-dollar pharma industry-fail to shift production to American soil in two years.

The US will impose 100% tariffs on generic drugs after two years and increase this to 200% after another year, Trump said in a social media post on Wednesday, over a year after he first proposed tariffs on pharmaceuticals. The aim is to "reshore" generic drug production to the US, with a "penalty" on companies that don't build capacity in the stated period, he said.

Stocks of top Indian drugmakers tumbled in early trade on Wednesday. Cipla traded 1.64% l...