“Russia has brought the world to the brink of a radiological catastrophe,” Zelensky told the United Nations.

US President Joe Biden will speak with Ukrainian President Volodymyr Zelensky on Thursday to brief him on US arms shipments and congratulate him on Ukraine’s independence day, according to the White House.

John Kirby, the communications coordinator for the National Security Council, said the United States would continue to “unite the free world” and “pull forward allies and partners” to support Ukraine as the Russian invasion hits the six-month threshold.

He confirmed that the phone call between Biden and Zelensky would reaffirm those commitments.

“The president is looking forward to it,” Kirby said, noting that there were no travel plans to discuss Biden’s visit to Kyiv. He noted that if the “journey makes sense”, it will be considered.

Today, Biden announced a nearly $3 billion security assistance package for Ukraine.

Warning of a possible next step in the Russian invasion, Kirby said the United States had information showing Russia was preparing to hold “mock referendums” in parts of Ukraine, possibly within days.

He said the announcement could come before the end of the week. Possible areas in which a referendum could be held include Kherson and Zaporizhia, along with Donetsk and Luhansk in eastern Ukraine.

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

He pointed out that the United States expects Russia to manipulate the results of the vote and falsely claim that the Ukrainian people want to join Russia.

“It will be necessary to denounce and combat this misinformation in real time,” he said.

He added that US data shows that Russian officials are concerned about low voter turnout in the upcoming vote.