President Biden surged $425 million to Ukraine’s defense against Russia on Wednesday as he prepared to travel to Germany to celebrate the unified front of Western allies.

Mr. Biden spoke by telephone to President Volodymyr Zelensky of Ukraine about the security package, which includes munitions, armored vehicles and other weapons, the White House announced.

The package comes as Mr. Biden is set to travel to Germany on Thursday for a brief trip that is likely to be his last visit to Europe as commander in chief. He will use the opportunity to remind the world of the importance of alliances just three weeks before the U.S. presidential election. Former President Donald J. Trump has criticized U.S. aid for Kyiv as he campaigns for another term in office.

Mr. Biden will meet with Chancellor Olaf Scholz and President Frank-Walter Steinmeier of Germany before returning to the United States on Friday.

In Mr. Scholz, Mr. Biden has found a reliable partner in efforts to support Ukraine and impose sanctions on Russia. Mr. Scholz has broken from Germany’s post-World War II hesitation on global security matters to emerge as one of the largest financial contributors to Ukraine’s war effort. But the support has come at a cost; the war has hit the auto and manufacturing sectors in Germany and rattled Mr. Scholz’s approval ratings.

The White House has also credited Mr. Scholz for playing a key role in a complex prisoner swap that helped free three Americans from Russia.

“The president really wanted to make sure to go to Germany to thank Chancellor Scholz directly,” said Karine Jean-Pierre, the White House press secretary.

Mr. Biden will also hold a virtual meeting to rally support for Ukraine with a larger group of Western leaders, which had been scheduled to be held in person last week at Ramstein Air Base in Germany. The president had to pull out of that meeting because of Hurricane Milton.

He is not expected to meet with Mr. Zelensky during the trip to Germany. Ms. Jean-Pierre did not say if Mr. Biden planned to hold meetings with other world leaders while in the country.

Mr. Biden will also travel to Luanda, Angola’s capital, during the first week of December, Ms. Jean-Pierre said, making good on a commitment to visit Africa before he leaves office.

Mr. Biden views Angola as a primary example of his administration’s efforts to revitalize relations with African nations after falling behind Russia and China in competing for security and economic influence on the continent. Africa has become increasingly important in the sphere of global competition, with the youngest, fastest-growing population in the world, and Angola specifically has turned to the United States recently for investment.