WASHINGTON — The United States has conducted defensive strikes on some Iranian targets in the Strait of Hormuz, a U.S. official said Monday, on the eve of crucial midterm elections. Iranian state television reported that explosions were heard on Qeshm Island. The official, who wasn’t authorized to comment publicly and spoke on condition of anonymity, said that “Iranians using surface to air missiles against U.S. assets” had been targeted. The strikes appeared to be limited as opposed to a return to full hostilities but followed President Donald Trump previously saying the U.S. would not launch new strikes on Iran before Tuesday's midterms. The unpopular war and the resulting impact on U.S. gasoline prices and other parts of the economy have been a vulnerability for Republicans as they try to keep control of Congress. The region is on edge about the prospects of the U.S. resuming full-scale operations against Iran, and the new strikes, which were reported earlier by The Wall Street Journal, are certain to raise fresh concerns. Backchannel negotiations also are playing out as Isra