A diplomatic scramble unfolded Saturday after President Donald Trump announced he would meet his Russian counterpart, Vladimir Putin, next week in Alaska, as European leaders rushed to understand the terms of the meeting and ensure Ukraine was not being left out of discussions about its future.

"We understand the Russians' intention to try to deceive America — we will not allow this," President Volodymyr Zelensky said in his evening address on Aug. 10.

Ukraine and its European allies sought on Sunday to present a united front ahead of a meeting this week between President Trump and President Vladimir V. Putin of Russia that risks sidelining Kyiv in future peace talks.