If Ukraine’s national security chief has his way, the war will end with Ukrainian tanks parked on Red Square in Moscow. Over the weekend, Oleksiy Danilov told the British newspaper The Sun, “Our tanks will be on Red Square and that will be justice.”

Danilov called Putin “Hitler’s twin,” and said the Russian leader is responsible for the war and the deaths of hundreds of thousands of people, including civilian men, women, children and elderly. This week, the United States government officially said Russia is committing war crimes in Ukraine.

Danilov said if Ukraine does not give Russia a “proper answer” for the invasion, it is only a matter of time before it invades another country.

Russia’s spring counteroffensive is now underway in Ukraine, but it doesn’t appear Putin is committing his full fighting force just yet. Ukraine and Western intelligence officials think Putin is timing the bulk of the offensive to coincide with the war’s one-year anniversary.

A report from the British Ministry of Defense said more than 800 Russian soldiers died every day last week. That’s the highest death toll since the start of the war. The Armed Forces of Ukraine said it has killed around 140,000 Russian soldiers since the war started, and wounded another 430,000.

Ukraine doesn’t publicly report its own casualties, but the U.S. Joint Chiefs of Staff put the number at around 100,000 back in November.

U.S. President Joe Biden made a surprise visit to Kyiv on Monday, in a defiant display of Western solidarity with Ukraine. The U.S. president spent more than five hours in the war-torn capital, consulting with Ukraine’s President Volodymyr Zelenskyy.

Speaking to Ukrainians while at a press conference, Biden said, “One year later, Kyiv stands and Ukraine stands. Democracy stands. The Americans stand with you, and the world stands with you.”

The Associated Press contributed to this report.