BNSF stopped issuing permits for trains carrying grain into Mexico between August 21 and September 20, before extending the policy through September 30.
If East and Gulf Coast ports are forced to shut down, the U.S. could see inventory shortages, higher costs at grocery stores, and months-long container backlogs.
Although Chinese-made software isn't common in American cars, the proposal is seen as a "targeted, proactive" move, said U.S. commerce secretary Gina Raimondo.
Russian intelligence targeted several European countries with sabotage attacks, often by hiring local criminals, officials previously told Bloomberg News.