At least three people, including the suspected attacker, have been killed in a bomb blast at a restaurant in central Moscow. 

Another 21 people were injured in the incident on Saturday.

Russia's National Anti-Terrorism Committee says a woman was trying to enter the restaurant with an improvised explosive device. 

Security guards stopped her at the entrance, and the bomb exploded. The woman, a security guard, and a customer were killed at the scene. 

Authorities have launched an investigation into the attack.