(AP) -- Russia's attack on a Ukrainian train station that killed more than 20 people this week is the latest in a series of strikes on the country's railway system that some international legal scholars say may be war crimes.
While Russia claimed that it had targeted the train because it was carrying Ukrainian troops and equipment on Wednesday, an Associated Press reporter on the ground said there was no visible indication that Ukrainian troops were among the dead, who included children. If civilians were the target, experts said Thursday, the attack could be considered a war crime.
"A train station is generally a civilian object and should not be a target of attack," said Jennifer Trahan, a clinical professor at New York University's Center for Global Affairs.
Wednesday's attack in Chaplyne, a small village in southeastern Ukraine, was one of the deadliest in months on the country's extensive railway system. In the more than six months since Russia invaded Ukraine, the AP and the PBS series "Frontline" have independently verified more than 40 attacks on civilian infrastructure that could be considered war crimes. Three of those hit the country's railway infrastructure and seven have involved local bus stops, killing more than 100 civilians. In these attacks, there has been little evidence to back up Moscow's claims that Ukrainian troops were the target.
The deadly strike Wednesday came as Ukrainians were defiantly celebrating their Independence Day while remaining on high alert because of threats that Russia would use the occasion to mount attacks.
This story is part of an ongoing investigation from The Associated Press and the PBS series "Frontline" that includes the War Crimes Watch Ukraine interactive experience and an upcoming documentary.
More than 50 people, including children, were on their way to flee Donbas when they were killed in a Russian attack on a train station in Kramatorsk in April. Photos from the aftermath showed dead bodies and abandoned luggage strewn around the station. Rail cars were crushed and hollowed out by fire.
Mykola Lukashuk, chair of the Dnipropetrovsk Regional Council, said during a press briefing Friday that the shelling in Chaplyne led to a fire in five carriages of the train. A family, including a 17-year-old daughter, was killed when its car was struck as it was traveling from Donetsk.
"People were being evacuated from Pokrovsk, Donetsk region, and a train was leaving from there to Lviv," Lukashuk said.
The deputy head of the Ukrainian presidential office, Kyrylo Tymoshenko, said Thursday that an 11-year-old boy died under the rubble of a nearby house and a 6-year-old died in a car fire by the station.
Tetyana Kvitnytska, deputy head of the Dnipropetrovsk regional health department, told the AP that those in Wednesday's attack had suffered head injuries, broken limbs, burns and shrapnel wounds.
"There is no such war crime that the Russian occupiers have not yet committed on the territory of Ukraine," Ukrainian President Volodymyr Zelenskyy said to the U.N. Security Council on Wednesday.
Russia's Defense Ministry said that an Iskander missile was used to carry out the attack and that 200 reservists "were destroyed on their way to the combat zone." An AP reporter who went to the scene said no Ukrainian troops were visible among the dead.
Even if some members of the military were among the dead, the attack could still violate the laws of war if it disproportionately harmed civilians.
"If you're going to kill a small number of troops as opposed to a large number of civilians, that's a war crime," said Michael Newton, a professor at Vanderbilt University's law school and director of the international legal studies program.
Iskander missiles are expensive precision guided missiles and are not used for trivial missions, said Frank Ledwidge, visiting fellow at the Transatlantic Dialogue Center in Kyiv and a former British military intelligence officer.
"The takeaway is a deliberate strike on a civilian target to cause civilian casualties for the purpose of disrupting rail traffic of civilians throughout Ukraine," he said.
In May, Russia used sea- and air-launched precision missiles to strike power facilities at five railway stations mostly in Lviv after claiming that the West was using the rail lines to deliver weapons to Ukraine.
It's not only the train stations that have become targets. Dozens of civilians waiting for buses have been killed in similar attacks. The AP has counted seven incidents where civilians waiting for a bus were killed. Photos of their bodies lying in pools of blood were shared across Telegram after the fact. In Mykolaiv, five people were killed and a dozen were injured at a bus stop during a Russian attack on July 29. Mykolaiv Mayor Oleksandr Senkevych said on Telegram at the time that Russian forces had fired cluster munitions at a crowded intersection around 10 a.m.
Editor's Note: The AP and "Frontline" are gathering information from organizations including the Centre for Information Resilience, Bellingcat, the International Partnership on Human Rights, the Ukrainian Healthcare Center and Physicians for Human Rights to inform the War Crimes Watch Ukraine interactive experience.