U.S. stock futures moved off their highest levels of the day and European stocks flattened out after President Trump tweeted he was bringing back steel tariffs on Brazil and Argentina. Trump also tweeted about the progress in stock markets since tariffs were introduced. Futures on the Dow Jones Industrial Average YM00, +0.16% were up 48 points, and the Stoxx Europe 600 SXXP, +0.01% was basically flat.