BEIJING — China announced on Wednesday that it would send a high-level diplomat to North Korea for the first time in two years, in a move less than a week after President Trump’s visit that is likely to resume pressure on the North to curb its nuclear arms program.

The head of the Communist Party’s external affairs department, Song Tao, is scheduled to leave for Pyongyang on Friday, China’s state-run news agency, Xinhua, reported. The official announcement said that Mr. Song would inform North Korea of the results of the 19th Communist Party congress last month that reappointed President Xi Jinping to a second term.

Xinhua also reported that Mr. Song would “visit” the north, a phrasing that Chinese specialists on international relations called an oblique way of saying that Mr. Song would carry a message from Mr. Xi. They said the message would most likely urge the North to join negotiations to halt its nuclear program, and convey the contents of Mr. Xi’s discussions with Mr. Trump about North Korea.

Last week in Beijing, the talks between President Xi and Mr. Trump focused heavily on North Korea. After he left Beijing, Mr. Trump tweeted that he was impressed with China’s efforts to push for the denuclearization of the Korean Peninsula. But it was unclear whether Mr. Xi had promised to take any new steps, as denuclearization has long been China’s policy goal there.

“I believe Song Tao will take a very clear message on the Trump summit with Xi Jinping,” said Cheng Xiaohe, professor of international relations at Renmin University of China in Beijing. “He will focus on North Korea needing to talk about denuclearization.”

North Korea’s KCNA news agency on Wednesday confirmed Mr. Song’s trip, a signal that after month’s of rebuffing Chinese attempts to send envoys to Pyongyang, the government of North Korea’s leader, Kim Jong-un, had agreed to Mr. Song’s visit.

But expectations were muted about whether the visit could move Mr. Kim to negotiate.

There was not even a guarantee that Mr. Song would see Mr. Kim in person, said Yang Xiyu, a Chinese diplomat who led the so-called six-party talks with North Korea more than a decade ago. He noted that it was most likely that the North Korean leader would only be willing to negotiate after conducting another missile test of the kind that has shaken the world this year.

“I am afraid that Kim will do something more terrible and will come to the negotiating table only after a big intercontinental ballistic missile test,” Mr. Yang said. “Then Kim will talk from a position of power.”

The last senior Chinese official to visit North Korea, Liu Yunshan, then a member of the elite Politburo Standing Committee of the Communist Party, appeared with Mr. Kim on the reviewing stand at a military parade in Pyongyang in October 2015. Mr. Liu made no headway then in curbing the North’s nuclear weapons expansion, and he retired last month. Mr. Song accompanied Mr. Liu and met the North Korean leader on that trip.

A lull in nuclear tests by North Korea since September has led to speculation, particularly in South Korea, that the North may be open to negotiations. But Chinese officials have been careful not to publicly encourage such assumptions.

Briefings to North Korea’s ruling Workers’ Party after China party congresses — held every five years — are routine.

The party officials who went to Pyongyang five and 10 years ago were of more senior rank than Mr. Song, though clearly this time Mr. Song’s mission is broader than a mere tally of last month’s proceedings, Mr. Yang said.

Now that Mr. Xi is firmly in place for his second term he will turn his hand to North Korea, Chinese experts said, in part to keep good relations with the United States.

If nothing else, Mr. Song should return with a reading of Mr. Kim’s intentions, Professor Cheng said.

“All the news commentaries from North Korea say North Korea will not negotiate,” he said. “If that’s the real intention, then China can make decisions. To get clear unambiguous information is the most important.”

Juecheng Zhao contributed research.