Jalina Porter, the State Department's deputy spokesperson, is responding to the Russian attack at a Ukraine train station that killed at least 50, saying, "We can no longer be surprised by the Kremlin's repugnant disregard for human life."

Five children were among those killed when Russian rockets struck the station in Kramatorsk in Donetsk Oblast on Friday morning, according to Ukraine's state-owned railway company. At least 100 people were injured, according to Donetsk Oblast Gov. Pavlo Kyrylenko.

Russia has denied involvement in the attack, which occurred as "thousands" of civilians fleeing the Russian invasion were at the train station waiting to be taken to "safer regions of Ukraine," according to Kyrylenko.

"Civilians are killed when they stay in their homes, and they're killed when they try to leave," Porter said. "Actions like these demonstrate why Russia did not belong on the U.N. Human Rights Council, and they also reinforce the U.S. assessment that members of Russian forces are committing war crimes in Ukraine."

Porter declined to say if the department considers the train station attack a war crime, saying, "Assessing individual criminal liability in specific cases is the responsibility of courts, as well as other investigatory bodies. But as the secretary, Secretary [of State Antony] Blinken, has said, 'Those responsible for war crimes and other atrocities committed in Ukraine will be held to account.'"

-ABC News' Conor Finnegan

At least 50 people, including five children, were killed in a rocket attack on a railway station in eastern Ukraine on Friday, authorities said.

Two Russian rockets struck the train station in the city of Kramatorsk in Donetsk Oblast on Friday morning, according to Ukraine's state-owned railway company, which in a statement via Facebook called the attack "a purposeful strike on the passenger infrastructure of the railway and the residents of the city of Kramatorsk."

Donetsk Oblast Gov. Pavlo Kyrylenko said 38 of the 50 killed died at the scene while 12 died in hospitals. At least 100 were injured, according to the governor.

The attack occurred as "thousands" of civilians fleeing the Russian invasion were at the train station waiting to be taken to "safer regions of Ukraine," according to Kyrylenko, who accused Russian forces of "deliberately trying to disrupt the evacuation of civilians."

"The evacuation will continue," the governor added. "Anyone who wants to leave the region will be able to do so."

Graphic images provided by Ukrainian officials showed the aftermath of the attack -- bodies lying on the ground next to scattered luggage and debris, with charred vehicles parked nearby. The remains of a large rocket with the words "for our children" in Russian painted on the side was also seen on the ground next to the main building of the station. Ukrainian President Volodymyr Zelenskyy said in a statement via Facebook that a Tochka-U short-range ballistic missile was used in Friday's attack.

Earlier this week, large crowds of people were seen waiting on the platform to board trains at the Kramatorsk railway station as they fled the city in Ukraine's disputed Donbas region.

Since 2014, Russia-backed separatist forces have controlled two breakaway republics of the Donetsk and Luhansk oblasts in the Donbas. The separatists have been fighting alongside Russian troops to seize more territory there, after Russia launched its invasion of Ukraine on Feb. 24. Now, the Russian military is said to be refocusing its offensive in the Donbas as its troops withdraw from northern Ukraine.

A senior U.S. administration official told ABC News that Russia isn't informing the majority of families when someone is killed in the war.

The official said mothers and spouses are starting to show up outside military bases to try to get information but are told to leave.

The official said mobile crematoriums are being used to burn the bodies of some Russian soldiers.

-ABC News' Martha Raddatz

The European Union announced Friday a fifth set of sanctions against Russian individuals and businesses, including a prohibition to buy and import coal and solid fossil fuels, with the package expected to include sanctions on Russian President Vladimir Putin’s two adult daughters.

The fresh sanctions also include a prohibition on Russian flagged ships accessing E.U. ports, further export bans on technologically goods and import bans on raw materials, accounting for billions of dollars.

Two E.U. officials told The Associated Press that Putin's adult daughters, Maria Vorontsova and Katerina Tikhonova, who were sanctioned by the United States earlier this week, have been hit with asset freezes and a travel ban. An E.U. spokesperson would not confirm to ABC News on Friday morning that Putin's daughters were among the latest individuals targeted, but said more details would be announced later in the day.

The bloc's top diplomat, Josep Borrell, said in a statement Friday that the "latest sanctions were adopted following the atrocities committed by Russian armed forces in Bucha and other places under Russian occupation."

"The aim of our sanctions is to stop the reckless, inhuman and aggressive behaviour of the Russian troops and make clear to the decision makers in the Kremlin that their illegal aggression comes at a heavy cost," Borrell added.

Meanwhile, the United Kingdom formally announced new sanctions against Putin’s two daughters as well as Russian Foreign Minister Sergei Lavrov, targeting the "lavish lifestyles of the Kremlin's inner circle."

"Our unprecedented package of sanctions is hitting the elite and their families, while degrading the Russian economy on a scale Russia hasn't seen since the fall of the Soviet Union," U.K. Foreign Secretary Liz Truss said in a statement Friday. "But we need to do more. Through the G-7, we are ending the use of Russian energy and hitting Putin's ability to fund his illegal and unjustified invasion of Ukraine."

"Together, we are tightening the ratchet on Russia's war machine, cutting off Putin's sources of cash," she added.

-ABC News' Guy Davies