President Donald J. Trump will meet China’s leader, President Xi Jinping, and Russia’s leader, President Vladimir Putin, together next week in Shenzhen, China, the White House said Friday. It will be the first time the leaders of the United States, China and Russia have ever met as a group of three.

The meeting is set for Thursday, Nov. 19. White House Assistant Press Secretary Olivia Wales shared the plans with reporters on a call about the trip. She said the meeting of all three leaders will be the last stop of the president’s visit to China. It will take place alongside the Asia-Pacific Economic Cooperation summit.

Ms. Wales said the president has made clear that he will talk about reducing the world’s nuclear weapons, along with other topics. She said he considers the spread of those weapons very dangerous.

A senior administration official, who spoke on the condition of not being named, said the president also plans to bring up Iran at the meeting. That is according to two news agencies, Agence France-Presse and Anadolu Agency.

The official said Ukraine is not expected to come up. The reason, the official said, is that China is not part of the separate talks between the United States and Russia.

“I would characterize this as the entry point, the first conversation, certainly at the leader level between these countries,” the official said, according to Anadolu Agency.

The official said Washington does not expect an agreement to come out of the talks. The official described China’s nuclear arsenal as “growing by far the fastest in the world.” The official also said it was time for Beijing to “step up to the adult table.”

Before the meeting of all three leaders, Mr. Trump and Mr. Xi will hold their own meeting and a working lunch on Thursday afternoon, Ms. Wales said. It will be the fourth time the two leaders have met since Mr. Trump returned to office, according to Agence France-Presse.

Officials said Mr. Trump is not scheduled to hold a separate one-on-one meeting with Mr. Putin.

Mr. Xi is hosting this year’s Asia-Pacific Economic Cooperation summit. It runs Nov. 18 and 19 in Shenzhen.

Officials said the president will leave Washington on Monday. On Tuesday, he will arrive in the Philippines for the summit of the Association of Southeast Asian Nations in Manila. After that, he will travel on to China.

Elon Musk will go with the president on the China trip, officials said. But he will not take part in the meeting with Mr. Xi and Mr. Putin.

On Sunday, the president said he expected to meet the two leaders in Shenzhen to discuss “a lot of things, including denuclearization.”