Russian Federal Security Service (FSB) said Monday that it has detained seven people suspected of involving in Islamic State (IS) terrorist group and plotting terrorist attacks in Russia's major cities.

The group of suspects, detained on Sunday in the central Russian city of Yekaterinburg, included citizens of Russia and Central Asian countries, said a FSB statement. They were led by an IS member from Turkey.

The intelligence agency said that a laboratory was found at their residence, along with components for improvised explosive devices and extremist literature.

The suspects intended to carry out terrorist attacks in Moscow and St. Petersburg, as well as in the Sverdlovsk region of the Ural Mountains, the FSB said.

It also confirmed that the suspected terrorists planned to flee to Syria after their plotted attacks, and join IS ranks in the war-torn country.

An investigation is underway to establish their criminal contacts.

Russia has strengthened security and anti-terror measures in major cities and several regions, as the IS threatened retaliation for Russia's airstrike mission in Syria, which began last September.