Russian state media now report that the Moscow restaurant blast was caused by a homemade explosive device, revising earlier uncertainty over its cause, with the death toll confirmed at three and 21 people injured, up from 15. Officials from Russia's National Anti-Terrorist Committee said a woman carrying the device tried to enter the Italian restaurant but was stopped by a security guard; the bomb then detonated, killing the woman, the guard and a restaurant visitor.

The explosion happened at around 20:00 local time on Kudrinskaya Square, at a restaurant inside one of Moscow's Stalin-era skyscrapers that was hosting a private function. Witnesses described seeing blood-covered people being carried out, while the restaurant later said there had been "a problem outside" rather than in the kitchen, as initially reported. Roads around the square were briefly closed, a planned evening cyclists' ride was cancelled, and RIA footage showed heavily armed law enforcement officers securing the cordoned-off scene.