Germany and other Ukrainian allies have lifted restrictions on Kyiv firing long-range missiles into Russia for the first time, the German chancellor said Monday, after days of Russia bombarding the capital and other regions with massive aerial attacks.

A Ukrainian official said Monday that an overnight Russian drone attack on Ukraine was the biggest of the three-year war.

Ukrainian officials described it as the largest aerial assault since Russia’s full-scale invasion of Ukraine in February 2022.

But two things could leave the alliance’s secretary general, Mark Rutte, presiding over a more difficult event: President Trump, who is expected to attend, is at odds with allies over Ukraine’s future. And Ukraine itself wants to join NATO, an outcome Mr. Trump opposes.