Russia's Federal Security Service (FSB) said on Saturday it had thwarted a large attack in the Urals city of Yekaterinburg and detained four teenagers it said had been planning to detonate a bomb in a crowded area.

The FSB said it had seized components for a homemade explosive device and that investigators in the Sverdlovsk region had opened a criminal case.

The four teenagers are Russian citizens born in 2007 and 2008, the FSB said. It did not name them.

The FSB said those detained "shared the ideas of a terrorist organization banned in Russia and planned to carry out a terrorist act using a homemade explosive device" in places where many citizens of Yekaterinburg are present.

It said that two of those detained had also been involved in an arson attack on an interior ministry car. The Interfax news agency reported that the arson attack had taken place on Dec. 22, 2024.