Russia's cruelty towards Ukrainian children who were victims of Russian aggression is the most shameful of its actions as part of a full-scale military invasion of Ukraine, President of Ukraine Volodymyr Zelenskyy said.

"Today, June 4, we remember the children who became victims of Russian aggression against Ukraine. Cruelty against them is the most shameful of actions. We will never forgive Russia for this," the president said in his Telegram channel.

As he noted, Russian terrorists took away the normalcy of life and shook the faith in adults of an entire generation of Ukrainian children.

"And many little Ukrainians will never become adults: Russian attacks took their lives. Thousands more were kidnapped from Ukraine, deported to Russia and scattered there among strangers. And, basically, they do not even have the opportunity to contact their relatives," Zelenskyy said.

At the same time, he said "Russian attitude towards Ukraine and Ukrainians is a conscious, calculated genocidal policy."

On June 4, Ukraine celebrates the International Day of Innocent Children, Victims of Aggression and the Day of Remembrance of Children Killed as a Result of the Armed Aggression of Russia against Ukraine.

According to the presidential press service, First Lady Olena Zelenska said since the beginning of the full-scale invasion in Ukraine, 550 children have died.

She once again appealed to the international community for help in saving the children, emphasizing that Ukraine cannot measure the cost of their lives by the cost of air defense.

"Our children need salvation. This salvation is a protected sky. This rescue is a punishment for their killers. This rescue is the release of 19,000 kidnapped children from Russian captivity. This salvation is a stop to aggression," Zelenska said while participating in an event to honor the memory of fallen children on the territory of the Memorial Complex "National Museum of the History of Ukraine in the Second World War."