US stock futures fell as President Trump threatened stiff tariffs on imports from more than a dozen countries and delayed the return of sweeping April levies.

What level of tariffs will the U.S. impose on imports and when? Stock futures were falling early Monday as markets were roiled by threats of new levies but also confusion over the deadline for the proposed duties.

U.S. stock-market futures declined as the Trump administration said a broad swath of tariffs against U.S. trade partners won’t take effect until Aug. 1, rather than July 9.