A woman allegedly tried to enter the premises with an explosive device, the country's national anti-terrorism agency said, according to Tass. The bomb was detonated when a security guard tried to stop her.
The woman, the guard and a guest were killed, according to the authority, which describes the bomb as "homemade".
The restaurant is located on Kudrinskaya Square, where one of Moscow's "Seven Sisters", the so-called Stalinist skyscrapers, stands.
The city's annual night bike festival has been canceled due to the incident.
The explosion occurred around 6 p.m. local time.
