The distinctive buzz of the Iranian-designed drones has become a familiar sound in Ukraine over the past four years. Now, it's increasingly heard across the Persian Gulf as Tehran strikes back with the cheap but effective weapons following the attack by the U.S. and Israel against Iran. The Shahed drones have made a transformative impact on the modern battlefield, with Russia sending swarms of the deadly weapons into the skies above Ukraine on nightly missions. While ballistic and cruise missiles fly much faster and pack a bigger punch, they cost millions and are available only in limited quantities. A Shahed drone costs only tens of thousands of dollars — a tiny fraction of a ballistic missile.

Russia is intensifying drone strikes on Ukraine's rail network, a critical lifeline for commercial freight, passenger traffic and military logistics. A recent "double tap" drone attack in northeast Ukraine, less than 43 miles from the Russian border, killed a 71-year-old man, injured at least eight people and destroyed train cars. Ukrainian officials say strikes have surged since the summer, driven by upgraded Russian drones equipped with cameras and radio modems that allow operators to detect air defenses and carry out precision strikes. Ukraine's rapid repair crews are keeping trains running, but experts warn that the continued strikes are likely to take a bigger toll on the country's transport and energy infrastructure.