A photo posted on Wednesday on Telegram by a regional governor showed a white vehicle with blown-out windows and a line of what appeared to be blood streaming down its side. Reuters has not verified the image.
"There is no military logic to this, just another act of brutality," Ukrainian President Volodymyr Zelenskiy said on social media, urging the US and Europe to toughen sanctions against Russia.
Moscow and Ukraine have traded strikes in recent months on logistics and other economic targets, aimed at hampering each other's war effort and damaging morale.
With Ukraine's airspace closed since Russia's full-scale invasion in 2022, buses and trains have become a vital transport link for Ukrainians and businesses.
The drone attack on the passenger bus near the frontline city of Nikopol killed four men and a woman early on Wednesday, police said.
Seven people were wounded in the attack, said the governor of the surrounding Dnipropetrovsk region, Oleksandr Hanzha, who posted the photo.
There was no immediate comment from Russia. Both Ukraine and Russia deny deliberately targeting civilians in the war, triggered by Moscow's full-scale invasion of its neighbour.
A Russian drone also attacked a passenger train in Ukraine's southern Mykolaiv region, the acting regional governor said.
All 168 passengers and crew were evacuated and no one was wounded, Heorhii Reshetilov said on Telegram. The train was attacked twice more after the first strike, he said.
Zelenskiy said, in addition to the Mykolaiv train attack, a locomotive in Kovel — near the border with Poland — was also struck.
The incidents follow similar attacks recently, including on a train near Ukraine's border with NATO-member Poland on Sunday, shortly after European diplomats and political figures had used the same line.
Regional officials reported other casualties through the afternoon and evening in various areas.
Russian shelling killed one person in southern Kherson region and the head of the city administration in the port of Odesa reported one dead. Russian attacks injured more than a dozen people in Sumy in the north and Kropyvnytskyi in central Ukraine.
The Russia-installed head of areas of Ukraine's eastern Donetsk region held by Moscow said a Ukrainian drone strike had killed one person. Officials in Russia's border Belgorod region said six people were injured in Ukrainian attacks.
Russia has intensified its attacks on Ukrainian railways, hitting 120 passenger wagons, 304 locomotives and 43 railway stations in 2026, the state rail operator told Reuters.
The company said Russia has attacked 1700 railway facilities in total since the start of the year, up from 1206 facilities in 2025 and 842 in 2024.
"Russian forces strike passenger trains, locomotives, stations, and railway routes knowing exactly how essential they are for civilians, evacuations, and Ukraine's economy," Ukraine's Foreign Minister Andrii Sybiha said on X.
"This is not collateral damage. It is a systematic hunt for people and an attempt to paralyse civilian life," he said.
10°C