KYIV, Ukraine-A Russian jet-powered drone struck a train close to Ukraine's border with Poland shortly after high-level European officials passed the same stretch of track, drawing condemnation from European capitals over what they called an escalation on the edge of NATO territory.

Also Sunday, President Trump called on Ukraine to ease up on strikes on Russian oil refineries that are contributing to an increase in diesel prices that could hurt his fellow Republicans in the midterms.

Russia's invasion of Ukraine, now advancing toward a sixth year, is entering a dangerous new phase as each side deploys more weapons with longer range that are affecting neighbors and allies.

Russia is increasingly poking European countries, members of the North Atlantic Treaty Organization, with covert attacks and threats that their territories-which serve as production centers and logistics routes for Ukraine-are fair game for targeting. Ukraine, for its part, is developing increasingly long-range drones and missiles that are damaging Russian energy infrastructure, including last week a gas plant in the Arctic almost 2,000 miles from Ukraine.

Ukrainian Railways said the Russian attack took place on a passenger train locomotive just over one mile from the Polish border on Sunday morning, adding that no one was injured because of a timely warning from a Ukrainian team monitoring the skies for threats.

The train was struck at Yahodyn station, where shortly before a train with security advisers from several European countries and former state leaders, including former British Prime Minister Boris Johnson, had passed through.

The diplomatic train departed earlier than expected "as part of real-time adjustments to train schedules due to the constant threat of Russian strikes," Ukrainian Railways said in a statement on the Telegram messaging app.

Polish Prime Minister Donald Tusk said at a briefing that Poland knew of the Russian plan to try "to disorganize, paralyze, and perhaps also destroy Ukrainian border crossings."

"The escalation on the part of the Russian Federation has become a fact, and its examples are getting closer to our border," Tusk said Sunday during a special briefing.

After the trip, former prime minister Johnson, a longtime champion of Ukraine, urged allies to support Ukraine with air-defense supplies and financial resources via the transfer of Russian frozen assets.

"I don't know what warped logic drove Putin to blow up a stationary Ukrainian locomotive on the Polish border this morning. What we can say for sure is that this is the kind of random and senseless attack Ukrainians are enduring every day-even on civilian railways," he said Sunday on X.

Johnson was in Kyiv to attend the Yalta European Strategy Conference, along with other dignitaries including national security advisoes from the U.K., Germany and France. Former Swedish Prime Minister Carl Bildt, who was also there, said the train he was on had an evacuation warning but could proceed to the border crossing.

In recent months, Russian forces have stepped up their aerial campaign, launching thousands of drones and hundreds of missiles that have struck many civilian targets including trains and gas stations. The introduction of faster jet-powered drones complicated the task for Ukraine, which had developed interceptor drones to take out earlier, slower craft.

An international shortage of interceptors for Patriot missile systems left Kyiv struggling to down incoming barrages of Russian ballistic missiles and promoted worries about attacks on energy infrastructure before winter.

Ukrainian President Volodymyr Zelensky said Russia had launched 78 missiles and around 2,100 drones, a significant share of them jet-powered, in around-the-clock attacks on the Ukrainian cities over the past week, damaging railway and energy infrastructure, gas stations, and residential buildings.

Ukraine meanwhile has been waging a long-range strike campaign against Russian oil refineries, warehouses, and military industrial plants in a drive to deplete Moscow's war chest and cripple the sectors underpinning its economy.

In August, Russia's refinery industry processed 3.8 million barrels of oil a day, a sharp drop from the 5 million barrels a day it handled the same month last year, according to Energy Aspects, a data and analysis firm.

Ukraine's military said it had attacked two oil refineries and a drone-storage facility in Russia on Sunday morning. Trump, under pressure from rising fuel prices at home, said that the U.S. told Zelensky Ukraine needs to stop hitting diesel fuel in Russia amid rising diesel prices.

"Mr. Zelensky has to do one thing," Trump said. "He has to stop knocking out diesel fuel in Russia, let him go after targets but not diesel fuel, because he's causing a shortage of diesel fuel."

Unclear is how much pressure Trump is willing-or able-to bring on Zelensky to cease the attacks. After Trump trimmed U.S. support for Ukraine, Kyiv is now more reliant on Europe for funding for the war. The U.S. still supplies intelligence and, via Elon Musk's Starlink, critical communications for Ukraine's military.