At least 50 killed in attack on Ukrainian train station

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

Two Russian rockets struck the station in 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 people killed died at the scene while 12 died in hospitals. At least 100 people were injured, according to the governor.

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.

Russia has denied involvement in the attack. Kremlin spokesman Dmitry Peskov claimed involvement of Russian forces was already ruled out by the Russian Ministry of Defense, based on the type of missile that was used -- a Tochka-U short-range ballistic missile.

"Our Armed Forces do not use missiles of this type," Peskov told reporters during a press briefing Friday. "No combat tasks were set or planned for today in Kramatorsk."

According to a senior U.S. defense official, the initial assessment by the U.S. is this was a short-range ballistic missile fired by Russian forces from inside Ukraine.

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."

Nate Mook, CEO of Chef José Andrés' World Central Kitchen, told CNN he was near the train station picking up supplies when the station was hit. He said he saw thousands of women, children and elderly waiting for a train, and less than two minutes later, he heard five to 10 booms.

Mook tweeted, "Innocent women & children were murdered here today."

White House press secretary Jen Psaki called the attack "yet another horrific atrocity" but stopped short of calling it a war crime without further investigation.

"Obviously the targeting of civilians would certainly be a war crime and we've already called a range of the actions we have seen to date a war crime, but we're going to be supporting efforts to investigate exactly what happened here," she said.

Psaki also said that although the sanctions package announced Wednesday was "augmented as a result of the atrocities" seen in Bucha, the administration would assess how this new attack would impact additional sanctions.

"What we have done to date and will continue to do is look at, unfortunately, the continued atrocities that we're seeing in the country and assess how that's going to impact sanctions, consequences, and obviously additional security assistance," she said. "And I'm certain given the video footage we have seen and on air waves across the world, and photos, that this will be a part of the discussion that our national security officials are having with their counterparts moving forward."

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 eastern 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.

ABC News' Luis Martinez, Armando Tonatiuh Torres-García and Brian Hartman contributed to this report.