Russia denied involvement in a rocket attack that killed dozens of people at a train station in eastern Ukraine on Friday.

Kremlin spokesman Dmitry Peskov alleged that the involvement of Russian forces in the attack on the railway station in the Ukrainian city of Kramatorsk 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."

The head of the European Commission, Ursula von der Leyen, and the bloc's top diplomat, Joseph Borrell, were due to arrive in Ukraine's capital on Friday.

While in Kyiv, the pair will meet with Ukrainian President Volodymyr Zelenskyy. It will be their first visit to the Ukrainian capital since Russia launched its invasion on Feb. 24.

At least 30 people were killed and more than 100 others injured in a rocket attack on a railway station in eastern Ukraine on Friday morning, authorities said.

According to Ukraine's state-owned railway company, two Russian rockets struck the train station in the city of Kramatorsk in Donetsk Oblast.

"This is a purposeful strike on the passenger infrastructure of the railway and the residents of the city of Kramatorsk," Ukrainian Railways said in a post on Facebook.

Donetsk Oblast Gov. Pavlo Kyrylenko said the station was teeming with civilians fleeing the Russian invasion. Kyrylenko accused Russian forces of wanting "to take as many peaceful people as possible."

"Thousands of people were at the station during the missile strike, as residents of Donetsk Oblast are being evacuated to safer regions of Ukraine," Kyrylenko said in a post on Telegram.

Ukrainian President Volodymyr Zelenskyy confirmed that "thousands of peaceful Ukrainians were waiting for evacuation" when the rockets hit the station.

"Not having the strength and courage to confront us on the battlefield, they are cynically destroying the civilian population," Zelenskyy said in a post on Facebook. "This is an evil that has no limits. And if it is not punished, it will never stop."

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.

Russian forces in northern Ukraine have now fully withdrawn to neighboring Belarus and Russia, the U.K. Ministry of Defense said Friday in an intelligence update.

"At least some of these forces will be transferred to East Ukraine to fight in the Donbas," the ministry added. "Many of these forces will require significant replenishment before being ready to deploy further east with any mass redeployment from the north likely to take at least a week minimum."

Meanwhile, cities in eastern and southern Ukraine continue to be shelled by Russian forces as the troops advance "further south from the strategically important city of Izium which remains under their control," according to the ministry.

White House national security advisor Jake Sullivan hinted Thursday of more sanctions coming against Russia in the "next week or two" aimed at targeting ways Moscow is evading sanctions already imposed.

“Where our focus will be over the course of the coming days is on evasion,” Sullivan said Thursday at the Economic Club of Washington. “As Russia tries to adjust to the fact that it’s under this massive economic pressure, what steps do they take to try to evade our sanctions and how do we crack down on that? And I think we'll have some announcements in the next week or two that identify targets that are trying to facilitate that evasion both inside Russia and beyond."

When Sullivan was asked whether sanctions will automatically be lifted if a negotiated peace deal between Russia and Ukraine is worked out, he appeared cautious with his words, saying, “a lot of that depends on what the shape and scope” of the agreement is.

“A lot of it depends on what the Ukrainians, in consultation with us and the Europeans come to agree to," Sullivan said. "You know, we're not going to do a deal over the head of the Ukrainians where we give a bunch of sanctions relief to Russia. But if some measure of sanctions relief were built in to some credible diplomatic solution led by the Ukrainians, that's something that we would happily discuss."

But Sullivan said Russian oligarchs shouldn't expect to ever get back their yachts and other assets seized under sanctions that have been imposed, saying the ultimate goal is "not to give them back” once the war is over.

“The president is actively looking at how we can deal with the fact that as we seize these assets, our goal is not to give them back. Our goal is to put them to a better use than that," Sullivan said. "But I'll be careful in what I say today because there's an ongoing kind of policy process around how we end up dealing with that question. But, rest assured, that the goal is not just to sit on them for a while."

-ABC News' Justin Gomez