The Russian authorities have detained an editor working for Radio Free Europe/Radio Liberty, an American broadcaster funded by the United States government, on charges of failing to register as a “foreign agent,” the media company said on Thursday.

The editor, Alsu Kurmasheva, who holds both Russian and United States citizenship, is the second American journalist to be detained in Russia this year. In March, Russian special services detained Evan Gershkovich, a Russian correspondent for The Wall Street Journal, on espionage charges, which he and The Journal have denied. He remains in a high-security prison in Moscow awaiting trial.

Ms. Kurmasheva’s detention, in Kazan, a major city about 500 miles east of Moscow, is likely to further raise suspicions that the Kremlin now views American citizens on its soil as high-profile assets that can be traded for high-value Russians held in United States custody.

“Another hostage has been taken,” Dmitri Kozelev, a prominent Russian journalist, said in his channel on the Telegram messaging app.

Russia’s increased anti-American stance was also on view on Thursday during a two-day visit by Foreign Minister Sergei V. Lavrov to Pyongyang, where he met with Choe Son-hui, North Korea’s foreign minister. During that meeting, Mr. Lavrov said that Russia admired North Korea’s “principled and unwavering support” of Moscow’s actions in Ukraine, where he said the United States was inciting a crisis, as it was also doing in other parts of the world, including the Middle East and the Asia-Pacific, according to a statement from Mr. Lavrov at the end of the visit.

In RFE/RL’s announcement of Ms. Kurmasheva’s detention, the broadcaster’s acting president described her as “a highly respected colleague, devoted wife and dedicated mother to two children.”

“She needs to be released so she can return to her family immediately,” the president, Jeffrey Gedmin, said in the statement.

The Russian authorities have not issued any statement about the arrest.

Ms. Kurmasheva lives in Prague with her husband and children, RFE/RL said. In May, she traveled to Kazan on “a family emergency.” About two weeks later, while trying to board a returning flight, she was temporarily detained and fined for failing to formally notify the Russian authorities about her United States citizenship.

Her American and Russian passports were confiscated at that time. According to the statement, she was awaiting their return when the new charges were announced on Wednesday.

If convicted, Ms. Kurmasheva could be sentenced to up to five years in prison, RFE/RL said.

Under Russian law, individuals and organizations receiving funding from abroad and engaged in loosely defined political activity must register as foreign agents or face prosecution. The law, passed in 2012, has been criticized by rights groups as a political tool used by the Russian government to suppress dissent and stigmatize perceived critics of the Kremlin.

Dmitri Anisimov, a spokesman for OVD-Info, a Russian rights group, said that the group expected a court to put Ms. Kurmasheva in pretrial detention, making her the first individual ever arrested on charges of violating the foreign agents legislation.

Tatar-Info, a Russian news agency, reported that Russian investigators believed Ms. Kurmasheva had been collecting information about the mobilization of Russian university teachers into the army, something that could then be used to discredit the country.

Russia’s state television said in its report about the arrest that most of Ms. Kurmasheva’s articles had been “dictated” by foreigners.

RFE/RL said that Ms. Kurmasheva had been covering ethnic minority communities in Tatarstan and Bashkortostan, two Russian regions where groups of people have sought greater autonomy from Moscow.

After the Russian invasion of Ukraine, Ms. Kurmasheva edited a book called “No to War” that featured stories of 40 Russians who opposed the invasion.

Anatoly Kurmanaev contributed reporting.