Russia’s foreign minister told Secretary of State Mike Pompeo on Saturday that charges against a woman accused of infiltrating American political organizations as a covert Russian agent were “fabricated” and she should be released.

The appeal by the Russian foreign minister, Sergey V. Lavrov, was made in a phone call, according to the Russian Foreign Ministry. The Department of Justice has charged the woman, Maria Butina, with acting as an unregistered agent of Russia while attending conventions of the National Rifle Association and gaining access to conservative circles in an effort to influence powerful Republicans.

Moscow has mounted a vigorous effort on behalf of Ms. Butina. On Thursday, the Foreign Ministry began a social media campaign on its Twitter account, declaring that it was mobilizing a digital “flash mob” to demand her release.

The State Department had no immediate comment on Saturday’s exchange, though it’s unlikely that the United States would suddenly release Ms. Butina. In a detailed indictment, the Justice Department has accused her of engaging in a series of deceptions over a number of years.