Two Central Asia natives were preparing terrorist attacks in Moscow and the Moscow Region on September 1, the first day of the academic year.
One of the Daesh terrorists intended to detonate himself in a crowd, the FSB announced.
"A powerful improvised explosive device and components for its manufacturing were found at his place of residence. He admitted he was going to become a suicide bomber," the security service specified.
The other individual wanted to attack civilians with a knife.
"One of the detained persons uploaded a video online in which he pledged allegiance to Daesh… Contacts with recruiters and instructions on the attack were found in his phone," the FSB said.
Russia remains threatened by Daesh and other terrorist groups, the FSB head said in early August.
Moscow has been conducting a military operation against terrorist groups in Syria since Septmeber 30, 2015, at President Bashar Assad's request.