The International Criminal Court was also called the West's "puppet body" by Russia after issuing an arrest warrant for President Vladimir Putin over Ukraine.
Ukrainian forces have withdrawn from some areas of the country’s east and battled Russian troops in others.
“We know this is a challenging time,” the U.S. Secretary of State said.
Russian President Vladimir Putin has proposed removing Defense Minister Sergei Shoigu from his post.
The renewed assault on the region has forced more than 1,700 civilians residing in settlements near the fighting to flee, according to Ukrainian authorities.
Since coming to power, the Russian president has made May 9 an important part of his political agenda, featuring displays of military might.
An American soldier has been arrested in Russia's port city of Vladivostok and accused of stealing from a Russian girlfriend, U.S. officials said.
Vladimir Putin is beginning his fifth term as Russian president after destroying his political opposition, launching a devastating war in Ukraine and consolidating power.
U.S. intelligence officials have determined that Russian President Vladimir Putin likely didn’t order the death of imprisoned opposition leader Alexei Navalny in February.
One push for getting the House speaker to allow a vote on aid centered on Russian invaders’ treatment of Ukraine’s small evangelical Christian community.