Three people were killed on Saturday at an upscale Italian restaurant in central Moscow following a massive explosion.
The explosion was caused by a homemade explosive device, Russia's National Anti-Terrorism Committee claimed.
The dead included a woman who attempted to bring the explosive device into the Balzi Rossi Italian restaurant, a security guard and a patron, Russian state news agency RIA Novosti reported, adding that the security guard wouldn't let her in.
At least 21 more people were injured in the explosion, which happened around 8 p.m. on a ground-floor terrace restaurant at Kudrinksaya Square, which includes seven skyscrapers built during the Stalin regime.
Balzi Rossi 's website said it was closed Saturday for a private event.
Russia's FSB security service said earlier this year that it planned to increase security within the country for high-level officials after a series of assassinations as the war in Ukraine drags on.
Heavily armed law enforcement was seen at the scene.
Moscow Investigative Committee told the news agency the scene is still under active investigation.
The Associated Press and Reuters contributed to this report.