Whitaker pointed out, however, that the decision must be made by Trump, but that "there is time to make that decision. No decision has been made".
In an interview with Fox News, US Vice President JD Vance says the White House is working to arrange a trilateral meeting between the leaders.
Four American sources tell NBC that the White House is considering inviting the Ukrainian president to Alaska.
At the same time, Germany's Chancellor says he expects Zelenskyj to participate in the summit.
"We hope and assume that the Ukrainian government, that President Zelenskyj, will participate in this meeting", Merz said in an interview with the TV channel ARD. He also says there that he will talk to Trump on Sunday.
Zelenskyj has previously warned that decisions made without Ukrainian representation are "stillborn". Several European leaders have repeated a similar message since the meeting was announced.
