Story highlights

Agency: The suspects were from Russia, central Asian nations and led by someone who'd come from Turkey

Searches of the suspects' houses turned up a bomb lab, guns, grenades and "extremist literature," state news says

ISIS has threatened attacks in Russia, which is involved in a military campaign against the terror group in Syria

CNN —  

An ISIS massacre on the streets of Moscow? Bombs detonated by the same terror group in St. Petersburg?

Such “huge terrorist acts” might have happened if Russian authorities hadn’t detained seven alleged ISIS members, state media reported.

The FSB – Russia’s security agency and the successor to the Soviet Union’s KGB – told state-run TASS news that the seven suspects were charged Wednesday for plotting terrorist attacks.

They’d been detained February 7 in Yekaterinburg, Russia’s fourth-largest city situated in the Sverdlovsk region in the Urals, according to a report by state-run Sputnik news citing the FSB.

To date, Russia hasn’t been hit by ISIS terror attacks on busy, civilian-filled areas like those in Paris, Tunis or Jakarta. But it has been a target, in part for the Kremlin’s armed efforts against the Islamist extremist group in Syria.

ISIS’ Caucasus affiliate claimed credit for a pair of attacks, one in September on a Russian military facility, and another a December shooting in the troubled Russian republic of Dagestan. And an ISIS affiliate in Sinai said that its members bombed a Russian passenger plane flying from Egypt to St. Petersburg, killing 224 people.

And in a five-minute video posted to ISIS-affiliated social media accounts (although not independently verified by CNN as authentic) in November, ISIS purportedly threatened to attack Russia “very soon.”

At that time, Kremlin spokesman Dmitry Peskov told reporters, “I’m sure this material will be subject of scrutiny by our special services.”

Bomb lab, grenades, guns discovered

The seven ISIS suspects charged in Yekaterinburg included citizens of Russia and central Asian nations, with the FSB indicating that their ringleader had come from Turkey.

They were ready to launch “high-profile terrorist attacks” in Moscow, St. Petersburg and around Sverdlovsk. Officials didn’t specify exactly where or when they’d planned to attack, though the FSB indicated they’d have used “homemade explosive devices.”

Searches of the suspects’ houses unearthed a bomb-making laboratory, electronic detonators, guns, grenades, bomb components and “extremist literature,” TASS reported.

After launching attacks in Russia, “those who were detained planned to leave for Syria to participate in military actions in the ranks of Daesh (or ISIS),” the FSB said.

While ISIS itself is relatively new, the threat from Islamist extremists in Russia is not. Chechen rebels have been blamed for much of it: the 2002 siege of a Moscow theater that ended with the deaths of 117 hostages; and in September 2004 at Beslan, where 330 people, more than half of them children, died and more than 700 people were wounded in the bloody climax of a school siege.

In addition to threats originating in its predominantly Muslim regions in the Caucasus, the Carnegie Moscow Center’s Nikolay Kozhanov has said Russia should also be concerned “about the possible return to Russia of the 2,000 or more Russian-speakers currently fighting” in Syria to topple President Bashar al-Assad.

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CNN’s Salma Abdelaziz and Alex Felton contributed to this report.