A railway worker looks at a heavily damaged train after a Russian attack on a train station Wednesday during Ukraine's Independence Day in the village Chaplyne, Ukraine, Thursday, Aug. 25, 2022. [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.