WASHINGTON — An American official said Monday that North Korea’s leader, Kim Jong-un, may travel to Russia soon to meet with President Putin as the Kremlin tries to acquire military equipment for use in its war in Ukraine.

The official, who was not authorized to address the matter publicly and spoke to the Associated Press on condition of anonymity, said the United States expects Mr. Kim will make the trip within the month. 

It is unknown where or when the meeting would take place, but the Pacific port city of Vladivostok would be a likely possibility given its relative proximity to North Korea.

A National Security Council spokeswoman, Adrienne Watson, noted Monday that Russia’s defense minister, Sergei Shoigu, traveled to Pyongyang last month and tried to persuade North Korea to sell artillery ammunition to Russia.

Ms. Watson said, “We have information that Kim Jong Un expects these discussions to continue, to include leader-level diplomatic engagement in Russia.”

She added that the U.S. is urging North Korea “to cease its arms negotiations with Russia and abide by the public commitments that Pyongyang has made to not provide or sell arms to Russia.”

Mr. Shoigu said Monday that the two countries may hold joint war games.

The New York Times first reported that Mr. Kim planned to meet with Mr. Putin in Russia this month.

The White House said last week that it had intelligence indicating that Messrs. Putin and Kim swapped letters following Mr. Shoigu’s visit. 

The National Security Council spokesman, John Kirby, said the letters were “more at the surface level” but that Russian and North Korean talks on a weapons sale were advancing.