By Kashish Tandon

(Reuters) -Indian pharmaceutical stocks fell 4.4% on Friday, wiping out gains from the previous session, after U.S. President Donald Trump threatened steep tariffs on the sector.

"Pharma (tariffs) is going to be starting to come in, I think, at a level that you haven't really seen before," Trump told reporters aboard Air Force One.

"That will be announced in the near future, and is under review right now," Trump said.

The index was among the top sectoral losers by percentage on the benchmark Nifty 50, which was down about 1.2% at 11:25 a.m. IST.

All 20 constituents of the pharma index were trading in the red, with Sun Pharma, Dr Reddy's and Cipla being the biggest drags.

Lupin, Aurobindo Pharma and Ipca Laboratories fell about 6.5% each, and were the top losers by percentage.

Trump imposed a 10% tariff on most U.S. imports earlier this week, as well as much higher levies on dozens of rivals and allies alike, but temporarily exempted some goods, including pharmaceuticals, benefiting major exporters including India, Japan and Ireland.

Pharma stocks were a rare bright spot on Thursday as global drugmakers gained on relief that their products remained temporarily shielded from the tariffs.

However, executives and analysts had warned it was premature to celebrate as levies were still likely to come.

"If these tariffs are introduced, the manufacturers will have no choice but to pass on the impact to consumers," said Vishal Manchanda, an analyst at Systematix Institutional Equities.

Indian drugmakers have been on a 'wait and watch' mode and also raised concerns on the difficulty in setting up manufacturing in the U.S., a move that would increase their costs.

Trump in his Wednesday address had predicted pharma companies would come "roaring back" to the U.S, and warned that "they got a big tax to pay" if they don't.