An explosion Saturday at a Moscow restaurant that killed three people and wounded 21 others was a bombing, Russia's national anti-terrorism committee said.

"A homemade explosive device blew up at a restaurant in Kudrinskaya Square in Moscow, killing three people," said the committee, quoted by the Tass state news agency.

The three people killed were a woman carrying the device into the restaurant, a security agent who stopped her and a customer.

Telegram channel Baza, known for its ties with Russian security forces, first talked about a gas explosion that would have come from the restaurant's kitchen.

The restaurant had been booked for a private birthday party and Alexandre Tchaïko, the commander of the Russian Air Force, was present, reports say.