“Russia has put the world on the brink of a radioactive disaster,” Zelensky told the UN.

U.S. President Joe Biden will speak with Ukrainian President Volodymyr Zelensky on Thursday, update him on U.S. armed vessels and congratulate him on Ukraine’s Independence Day, the White House said.

John Kirby, communications coordinator for the National Security Council, said the United States will continue to “unite the free world” and “pull friends and partners forward” in support of Ukraine as the Russian invasion reaches the six-month mark.

He promised that a phone call between Biden and Zelensky would reaffirm those commitments.

“The president is looking forward to it,” Kirby said, adding that Biden has no travel plans to visit Kiev. He indicated that if a trip made sense, it would be considered.

Biden today announced a nearly $3 billion defense aid package for Ukraine.

Kirby warned of the next step in the Russian invasion, saying the US had information that Russia was preparing to hold “fake referendums” in parts of Ukraine.

He said an announcement could come by the end of the week. Kherson and Zaporizhia, along with Donetsk and Luhansk in eastern Ukraine, are the most likely areas for a referendum.

“The United States and the international community have made it very clear that any attempt to control Ukraine’s sovereign territory will not be considered legitimate,” Kirby said.

He noted that the United States expects Russia to manipulate the vote and falsely claim that the people of Ukraine want to join Russia.

“This misinformation needs to be condemned and countered in real time,” he said.

He said U.S. data showed Russian officials were concerned about low turnout in the upcoming referendum.