An explosion near a summer cafe in central Moscow killed three people and injured 15 on August 1, the interior ministry said.

The blast struck a crowded venue in the heart of the Russian capital during what witnesses described as a private wedding celebration, though authorities have not established a cause. Explosions in central Moscow are rare, and the incident comes against the backdrop of the war in Ukraine, which has brought drone attacks on the city in recent years.

"According to available information, an explosion occurred near a summer cafe at about 20:10 today, as a result of which three people were killed and 15 were injured in various degrees of severity," an interior ministry official from the Moscow branch said.

The explosion happened in a building on Kudrinskaya Square, with the epicentre in or near the Balzi Rossi restaurant and its outdoor cafe, according to preliminary information. Rescuers entered the building and carried out the injured by hand and on stretchers.

The Investigative Committee said the exact number of casualties and the circumstances were being established, and that investigators and forensic specialists were inspecting the site.

Alexey Kuznetsov, an aide to the health minister, said the wounded were receiving medical care.

Witnesses said about 50 people may have been inside the restaurant, which was hosting a wedding with about 15 security guards, Izvestia reported. Panic followed the blast, and ambulances arrived quickly.

Authorities closed several streets near the Garden Ring and postponed a night cycling festival that had been planned in the city.