The White House on Thursday cautioned Americans against traveling to Russia in the wake of reports that Russian authorities had detained a Wall Street Journal reporter.

“We are deeply concerned by the troubling reports that Evan Gershkovich, an American citizen, has been detained in Russia,” press secretary Karine Jean-Pierre said in a statement.

The White House and State Department has been in touch with Gershkovich’s employer and family, as well as the Russian government.

“I want to strongly reiterate that Americans should heed the U.S. government’s warning to not travel to Russia,” Jean-Pierre said. “U.S. citizens residing or traveling in Russia should depart immediately, as the State Department continues to advise.”

John Kirby, a White House spokesperson on national security issues, separately urged Americans to “heed the U.S. government’s warning not to travel to Russia.”

“I know of no efforts to tell other outlets to remove their journalists from Moscow,” Kirby said on a briefing with reporters. “We understand that you all have an important job to do, and in doing that job, all of you are willing to and must take risks. We respect that. But it doesn’t change our deep concern about the presence of Americans being in Russia.”

The State Department in February issued an advisory for U.S. citizens residing in Russia or traveling there to depart immediately, citing the risk of wrongful detentions.

Gershkovich’s arrest was reported by the Wall Street Journal early Wednesday morning, citing a statement from Russia’s main security agency, the FSB, that it had detained Gershkovich for espionage. 

The Journal “vehemently” denied the allegations and called for Gershkovich’s immediate release.