A senior official in the Russian cyberintelligence department that American officials say oversaw last year’s election hacking has been arrested in Moscow on charges of treason, a Russian newspaper reported Wednesday.

The arrest of Sergei Mikhailov, a senior officer of the Federal Security Service, or F.S.B., the main successor agency to the K.G.B., is a rare instance of turmoil in the country’s usually shadowy cybersecurity apparatus slipping into public view.

Mr. Mikhailov served in the F.S.B.’s Center for Information Security, the agency’s cyberintelligence branch, which has been implicated in the American election hacking. But it is not clear whether the arrest was related to those intrusions.

He was detained along with one of Russia’s leading private-sector cybersecurity experts, Ruslan Stoyanov, the head of computer incident response investigations at the Kaspersky Lab, which makes antivirus programs.