The U.S. ambassador visits Evan Gershkovich, a WSJ reporter detained in Russia.

The U.S. ambassador to Russia met Friday with Evan Gershkovich, the Wall Street Journal reporter jailed in Moscow, a few days after his family appealed to the United Nations for help in bringing him home.

The U.S. embassy in Russia confirmed the visit by Ambassador Lynne M. Tracy, which was the fourth time she had met with Mr. Gershkovich since he was detained by the Russian authorities in March.

“He remains strong and is keeping up with the news — including his parents’ appearance at the U.N. this week,” the embassy said in a statement on social media.

Mr. Gershkovich’s family on Wednesday had urged world leaders who will soon be attending the U.N. General Assembly to join the call for his release.

“Next week, world leaders will gather here to discuss many important issues,” Mr. Gershkovich’s father, Mikhail, said in New York . He called on those leaders to stand with his son, who he said represented “the basic right to free press and freedom of expression” — rights that are “bedrock principles of the United Nations.”

Lawyers filed a petition on Tuesday asking a group of U.N. experts to side with the American government and agree that Evan Gershkovich was being arbitrarily detained by Russia in violation of his human rights, the family said.

The petition was submitted to the U.N. Working Group on Arbitrary Detention, a panel of five human rights and international law experts. The group has previously evaluated the detentions of several journalists, including the Washington Post reporter Jason Rezaian, who spent 544 days imprisoned in Iran before he was released in a prisoner swap in early 2016.

The U.N. group does not have any enforcement authority, but its determination that Mr. Gershkovich is being arbitrarily detained would further raise pressure on Russia, already isolated from the West, to free him.

Ms. Tracy last met with Mr. Gershkovich in mid-August. American officials have said that their Russian counterparts are blocking them from getting regular consular access to Mr. Gershkovich, the first American journalist arrested on an espionage charge in Russia since the end of the Cold War. The United States government considers him wrongfully detained and, along with The Journal, has categorically denied the accusations against him.

Mr. Gershkovich’s pretrial detention will extend at least until Nov. 30, a Moscow court ruled last month after a secret proceeding that was closed to the news media. That court is scheduled to hear an appeal of that pretrial detention extension on Tuesday, according to The Journal.

The Kremlin has acknowledged that Russia could be open to a prisoner swap for Mr. Gershkovich.

Edward Wong contributed reporting.