Trains carrying Boris Johnson and foreign dignitaries were the intended targets of a Russian drone attack in Ukraine, experts fear.The former Prime Minister was on a charter train from Kyiv when it received a drone alert as it approached the Polish border.Amid fears of a targeted attack, a last-minute timetable change allowed it to speed across the border into Poland earlier than scheduled.Just over an hour later, a train on the same route was evacuated, with terrified passengers forced to run for safety as a nearby stationary locomotive exploded in flames after being struck. The jet-propelled drone hit only a mile inside Ukrainian territory. No-one was injured.Security experts said last night the near-miss could be 'a Mafia-style message straight from the Kremlin' aimed at Mr Johnson – a staunch supporter of Ukraine who was returning from a security conference in Kyiv.But a defiant Mr Johnson told the Daily Mail: 'Nothing will deter me from using Ukrainian railways or going back to Ukraine.'Passengers on the charter trains included UK national security adviser Jonathan Powell and former CIA chief David Petraeus. Former Swedish prime minister Carl Bildt said passengers on his train had been told to prepare for evacuation, but were then allowed to continue their journey.The terrifying escalation demonstrates that Vladimir Putin is 'playing with fire right on the border of the European Union and Nato', said a German MP who was on the same train as Mr Johnson. A rail worker is seen assessing the damage after a train was hit by a Russian missile near the Ukrainian border with Poland Frantic footage shared to social media showed passengers desperately fleeing the train prior to the attack This photo shows the damage to the front of the locomotive in the aftermath of the drone strike It is now feared that an earlier train carrying Boris Johnson (pictured last week) and other political figures was the target of the attack