In a smaller, closed-door meeting on Thursday, Republican lawmakers asked Mr. Zelensky to address their concerns and provide them with his vision of a plan for victory. And Democrats asked him how they could convince their conservative colleagues that continuing to support the war was the right answer.

Senator John Cornyn, Republican of Texas, said Mr. Zelensky had listened to questions about “funding fatigue,” and then talked about the “consequences of us cutting off the money.”

He said Mr. Zelensky had stressed that Europe and other countries look to the United States for leadership, and a decision by Washington to curtail aid could undercut Europe’s commitment.

Later, Mr. Zelensky brought his wife, Olena, to the meeting at the White House.

The Zelenskys have tried to build personal relationships with the president and Jill Biden, the first lady. Olena Zelenska has spent much of her time in hiding since the beginning of the war, but she has written letters to Dr. Biden, and the two of them met last year in Ukraine when the first lady took a secret trip to the country.

“It’s good that our countries are really truly allies,” Mr. Zelensky said, reading from a set of cards as he sat next to the president. “I am in Washington to strengthen Ukraine’s position to defend our children, our families, our homes, freedom and democracy in the world.”

Mr. Zelensky also recounted his “frank, constructive dialogue” earlier today with members of Congress from both parties. He posted a picture of himself with the House leaders, and emphasized that Ukraine is “sincerely grateful to the House, both parties, and the entire American people for all the support.”

Karoun Demirjian, James C. McKinley Jr. and John Ismay contributed reporting.