U.S. stock index futures were lower on Tuesday after President Donald Trump's comments on potential pharma tariffs renewed worries of the impact of a trade war, while some downbeat corporate results also weighed on investor sentiment.

U.S. stock index futures indicated a lower open on Tuesday after President Donald Trump's latest plans for pharma tariffs, further dampening investor sentiment amid subdued corporate earnings. Trump said late on Monday that he would announce pharma tariffs over the next two weeks,

Trump announced a 100% tariff on movies produced outside the U.S. but offered little clarity on how the levies would be implemented. Movie and television production companies that film overseas fell in premarket trading.