Busses promised by Russia to evacuate people from Mariupol did not arrive on Saturday.

At least 200 Mariupol residents had gathered near the Port City shopping center to be evacuated to Zaporizhia, adviser to the mayor of Mariupol Petro Andryushchenko said on Facebook.

“Instead of the buses promised by the Russian side, the Russian military approached Mariupol residents and ordered them to go away because "there will be shelling now." In fact, with rough coercion, they dispersed people. The buses were not submitted for loading,” he wrote.

Despite the increased activity, Russian forces have made no major gains in the last 24 hours as Ukrainian counterattacks continue to hinder their efforts, according to the UK Ministry of Defense.

Russian air and maritime forces have not established control in either domain, owing to the effectiveness of Ukraine’s air and sea defense.

Despite their stated conquest of Mariupol, heavy fighting continues to take place frustrating Russian attempts to capture the city, further slowing their desired progress in the Donbas.

United Nations Secretary-General Antonio Guterres will meet with Ukrainian President Volodymyr Zelenskyy and Foreign Minister Dmytro Kuleba in Kyiv on April 28.

Guterres will also meet with staff of U.N. agencies to discuss scaling up humanitarian assistance to the people of Ukraine.

The Russian Defense Ministry announced that one servicemember died and another 27 crew members went missing from its Black Sea Fleet flagship vessel Moskva last week.

"The remaining 396 crew members were evacuated from the cruiser to the ships of the Black Sea Fleet," the defense ministry said Friday.

The warship sank on April 14 following what the Ukrainians claimed was a missile attack. Russia did not acknowledge an attack on the ship and continued to say a fire broke out after ammunition detonated.

The defense ministry's latest announcement contradicts its earlier statement that all Moskva crew members had been rescued.

-ABC News' Somayeh Malekian

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