Russia's Federal Security Service (FSB) said on Wednesday it had detained 19 suspected militants planning attacks in the North Caucasus.
The FSB said it had seized a suicide belt, homemade bombs and automatic weapons from the suspects this month.
The 19 detainees were spread across the Rostov, Krasnodar and Karachay-Cherkessia regions, as well as Crimea, the peninsula Moscow annexed from Ukraine in 2014.
Footage from the detentions published by Russian news agency RIA showed FSB operatives scaling an apartment building and entering through a window to detain a suspect.
Russia has repeatedly been targeted by militant groups, including in an attack on a train carriage in a St Petersburg metro tunnel in 2017.