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.