April 9 (Reuters) - Indian pharmaceutical stocks .NIPHARM fell 1.7% on Wednesday after U.S. President Donald Trump reiterated plans to announce a "major" tariff on all pharmaceutical imports.

U.S. accounts for a third of India's overall pharma exports.

Trump also threatened the duties on Friday, after his first set of reciprocal tariffs earlier last week exempted pharma products -- a change in stance that had prompted a wild swing in pharma stocks.

On the day, all twenty constituents of the pharma index were lower, with the index dragging down the benchmark Nifty 50 .NSEI by about 0.52% as of 9:20 a.m. IST.

Gland Pharma GLAD.NS, Lupin LUPN.NS and Zydus Lifesciences ZYDU.NS were the top losers by percentage, down between 3% and 5%.

Sun Pharma SUN.NS and Cipla CIPL.NS, the top constituents by weight, fell 1.69% and 1.87%, respectively.

India's pharma exports to the U.S. mostly comprise generics, or cheaper versions of popular drugs. These currently attract almost no U.S. levies, while India imposes about 10% tax on U.S. pharma imports, according to industry experts.

The pharma index has fallen 14.4% this year.

(Reporting by Kashish Tandon and Ananta Agarwal in Bengaluru; Editing by Savio D'Souza)

((Ananta.agarwal@thomsonreuters.com;))