Those held were suspected of planning to hit "the railway system and major public gathering places" in Russia's second city, the FSB said in a statement.
Russia has stepped up security since a suicide bomb attack in the Saint Petersburg subway killed 15 and injured dozens on April 3.
The alleged perpetrator, Akbarjon Djalilov, was a 22- year-old Russian citizen who was born in ex-Soviet Kyrgyzstan in Central Asia.
The bombing was claimed by a little-known group, the Imam Shamil Battalion, which experts say is linked to al-Qaeda.
Citizens of Central Asia have been prominent among foreign fighters who headed to Syria and Iraq to fight for jihadist groups.
Russia hosts large populations of mainly migrant workers from ex-Communist Central Asia and they face frequent harassment and discrimination in the country.
The Russian security services regularly announce that they have thwarted plans for attacks.
The prosecutor's office said today that twelve attacks have been foiled on Russian soil since the beginning of the year, state news agency RIA Novosti reported.
Disclaimer: No Business Standard Journalist was involved in creation of this content
You’ve reached your limit of {{free_limit}} free articles this month.
Subscribe now for unlimited access.
Already subscribed? Log in
Subscribe to read the full story →
Smart Quarterly
₹900
3 Months
₹300/Month
Smart Essential
₹2,700
1 Year
₹225/Month
Super Saver
₹3,900
2 Years
₹162/Month
Renews automatically, cancel anytime
Here’s what’s included in our digital subscription plans
Exclusive premium stories online
Over 30 premium stories daily, handpicked by our editors


Complimentary Access to The New York Times
News, Games, Cooking, Audio, Wirecutter & The Athletic
Business Standard Epaper
Digital replica of our daily newspaper — with options to read, save, and share


Curated Newsletters
Insights on markets, finance, politics, tech, and more delivered to your inbox
Market Analysis & Investment Insights
In-depth market analysis & insights with access to The Smart Investor


Archives
Repository of articles and publications dating back to 1997
Ad-free Reading
Uninterrupted reading experience with no advertisements


Seamless Access Across All Devices
Access Business Standard across devices — mobile, tablet, or PC, via web or app
