The country's President Volodymyr Zelensky told Luxembourg's Parliament on Thursday that Russian troops now control 20% of the territory.
Zelensky said in his address that the Russian army has destroyed the eastern Ukrainian region of Donbas.
He said tens of thousands of Ukrainians have died in the war.
According to the Office of the United Nations High Commissioner for Human Rights, a total of 4,149 Ukrainian civilians have been killed and almost 5000 injured in the conflict.
According to Zelensky, Russia has lost more than 30,000 soldiers in the war, while NATO and the United Kingdom estimate Russian troop losses at 15,000.
On the same day Zelensky spoke, Good Morning America aired an interview with Zelensky's wife, Olena Zelenska, who said more than 200 children have been killed as a result of Russia's invasion.
It's not possible to concede parts of your territory. Zelenska said in the interview that it was like giving up a freedom.
There are accurate civilian and troop deaths in Russia. At the end of March, the Defense Ministry estimated Russia's army deaths to be over 1,300.
More than 6 million. That is how many people have left the country since the beginning of the war.
Zelenska said she has not seen her husband in a long time. She said she was proud that the world has been able to see Zelensky's "true identity." They have been married for nearly two decades.
Zelensky spoke as battles rage on in the eastern Ukrainian city of the same name, where Russian forces have made significant gains. Zelensky said fighting continues in the second largest city of Kharkiv in the east and in the city of Mykolaiv in the south. According to the New York Times, the Territorial Defense Force has had to fill holes in the frontline. Zelensky said the battle in the Donbas region was incredibly difficult. More than 8 million people have been internally displaced due to the war in Ukraine. The death toll in the city of Mariupol has been estimated by local authorities at over 10,000.
The Ukrainian first lady sat down for an interview with ABC News.
Zelensky said that Russian forces hold 20% of Ukrainian territory.
A whistle followed by a deadly onslaught. The soldiers are under attack. The New York Times is a daily newspaper in the United States.